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  • 1. Adesiyun, Adewole
    et al.
    Bezuglyi, Artem
    Bidnenko, Natalya
    Laszlo, Gaspar
    Golovko, Sergyi
    Kraszewski, Cezary
    Krayushkina, Kateryna
    Kushnir, Olexander
    Kuttah, Dina K
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Szpikowski, Miroslaw
    Andrezj, Urbanik
    Voloshyna, Iryna
    Vozniuk, Andrii
    Vyrozhemsky, Valeriy
    Short-term Research Visits2014Report (Other (popular science, discussion, etc.))
  • 2.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Bolling, Anne
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Andersson, Anders
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle technology and simulation.
    Validating speed and road surface realism in VTI driving simulator III2012Report (Other academic)
    Abstract [en]

    New simulator models concerning vibration, noise and graphics have been designed and implemented in the VTI Simulator III. The objective of this study is to validate this simulator in terms of road surface realism. Twenty-four drivers participated in the study and drove the same route both in the simulator and on real roads. Three road sections ranging from very smooth to rather uneven were incorporated in the design. The comparison included the objective driving parameter speed as well as subjective parameters from questionnaires and rating scales (evenness, quietness and comfort level). A road section with five speed limit changes was of particular interest in the analyses. No statistically significant difference could be found between the simulator and the car, neither in the parameter speed (in sections with no speed limit changes) nor in the ratings evenness and quietness. Despite similar speed profiles surrounding the speed limit signs, there was a statistically significant difference between the speed in the car and in the simulator, with more rapid accelerations and decelerations in the simulator. The comfort rating was shown to be higher in the car compared to the simulator, but in both cases the general trend showed higher comfort on smoother roads. These results indicate absolute validity for the ratings evenness and quietness, and for the measure speed, and relative validity for comfort and speed surrounding speed limit signs.

  • 3.
    Ahmed, Abubeker
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Full scale accelerated pavement tests to evaluate the performance of permeable and skeletal soil block pavement systems2016In: The Roles of Accelerated Pavement Testing in Pavement Sustainability: Engineering, Environment, and Economics, Springer International Publishing , 2016, p. 131-144Chapter in book (Other academic)
    Abstract [en]

    The increasing proportion of paved surface due to urbanization means that the conditions for urban trees and vegetation to survive have deteriorated. Factors such as air pollution, poor drainage, and the lack of usable soil for root growth contribute to the short life expectancy of urban trees. To meet this challenge, several permeable and "structural" or "skeletal soils" have been developed as alternatives to the typical compacted soil required to bear the weight of vehicular traffic in urban areas. The main objective of this study is to evaluate the resistance to permanent deformation of permeable and skeletal soil pavement structures based on full scale accelerated pavement tests (APT) using a heavy vehicle simulator (HVS). Interlocking paving stones of various types were used as permeable surface layer for the test structures. The results demonstrated that the permeable test structures exhibited higher permanent deformation than the corresponding impervious structures. The skeletal soil with bituminous base layer, however, produced performance comparable to the impervious reference test structures.

  • 4.
    Ahmed, Abubeker W.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
    Mechanistic-Empirical Modelling of Flexible Pavement Performance: Verifications Using APT Measurements2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing  the   time consuming parts of the MLET processes. A comprehensive comparison of the developed program with  two  widely  used  programs  demonstrated  excellent  agreement  and  improved  computational performance.  Moreover,  the  program  was  extended  to  incorporate  the  viscoelastic  behaviour  of bituminous materials through elastic-viscoelastic correspondence principle. A procedure based on collocation of linear viscoelastic (LVE) solutions at selected key time durations was also proposed that improved the computational performance for LVE analysis of stationary and moving loads. A comparison  of  the  LVE  responses  with  measurements  from  accelerated  pavement  testing  (APT) revealed a good agreement. Furthermore the developed response model was employed to evaluate permanent deformation models  for  bound  and  unbound  granular  materials  (UGMs)  using  full  scale  APTs.  The  M-E Pavement  Design  Guide  (MEPDG)  model  for  UGMs  and  two  relatively  new  models  were evaluated  to  model  the  permanent  deformation  in  UGMs.  Moreover,  for  bound  materials,  the simplified  form  of  the  MEPDG  model  for  bituminous  bound  layers  was  also  evaluated.  The measured  and  predicted  permanent  deformations  were  in  general  in  good  agreement,  with  only small discrepancies between the models. Finally, as heavy traffic loading is one of the main factors affecting the performance of flexible pavement, three types of characterizations for heavy traffic axle load spectrum for M-E analysis and design of pavement structures were evaluated. The study recommended an improved approach that enhanced the accuracy and computational performance.

    List of papers
    1. Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests
    Open this publication in new window or tab >>Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests
    2013 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 14, no 1, p. 178-195Article in journal (Refereed) Published
    Abstract [en]

    Mechanistic-empirical (M-E) pavement design methods have become the focus of modern pavement design procedure. One of the main distresses that M-E design methods attempt to control is permanent deformation (rutting). The objective of this paper is to evaluate three M-E permanent deformation models for unbound granular materials, one from the US M-E pavement design guide and two other relatively new models. Two series of heavy vehicle simulator (HVS) tests with three different types of base material were used for this purpose. The permanent deformation, wheel loading, pavement temperature, and other material properties were continuously controlled during the HVS tests. Asphalt concrete layers were considered as linear elastic where stress-dependent behaviour of unbound materials was considered when computing responses for the M-E permanent deformation models with a nonlinear elastic response model. Traffic wandering was also accounted for in modelling the traffic by assuming it was normally distributed and a time-hardening approach was applied to add together the permanent deformation contributions from different stress levels. The measured and predicted permanent deformations are in general in good agreement with only small discrepancies between the models. Model parameters were also estimated for three different types of material.

    Place, publisher, year, edition, pages
    Taylor & Francis Group, 2013
    Keywords
    Rutting (wheel), Unbound base, Granular, Stress (in material)
    National Category
    Infrastructure Engineering
    Research subject
    Road: Highway design, Road: Pavement design; Road: Materials, Road: Aggregate and stone materials
    Identifiers
    urn:nbn:se:vti:diva-6941 (URN)10.1080/14680629.2012.755936 (DOI)
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2017-12-05Bibliographically approved
    2. Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements
    Open this publication in new window or tab >>Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements
    2012 (English)In: Advances in Pavement Design Through Full-Scale Accelerated Pavement Testing / [ed] Jones, Harvey, Mateos & Al-Qadi, London: Taylor & Francis Group, 2012, p. 493-503Conference paper, Published paper (Refereed)
    Abstract [en]

     A response model to be employed in a mechanistic-empirical pavement performance predictionmodel based on multilayer elastic theory has been developed. An iterative approach using a method of successiveover-relaxation of a stress dependency model is used to account for the nonlinear behavior of unbound materials. Asphalt and subgrade materials are assumed to be linear elastic. The response model was verified against two series of Heavy Vehicle Simulator (HVS) response measurements made under a variety of wheel loadconfigurations and at different pavement temperatures. A comparison with Falling Weight Deflectometer (FWD)data was also carried out. The model was subsequently used to predict permanent deformation from the HVS testing using simple work hardening models. A time hardening approach has been adopted to combine permanentdeformation contributions from stress levels of different magnitude.The response model outputs and the predictedpermanent deformations were generally in good agreement with the measurements.

    Place, publisher, year, edition, pages
    London: Taylor & Francis Group, 2012
    Keywords
    Pavement, Simulation, Deflectograph, Model
    National Category
    Civil Engineering
    Research subject
    Road: Highway design, Road: Pavement design
    Identifiers
    urn:nbn:se:vti:diva-6942 (URN)10.1201/b13000-61 (DOI)ISBN 978-0-415-62138-0 (ISBN)
    Conference
    The 4th International Conference on Accelerated Pavement Testing
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2014-08-22Bibliographically approved
    3. Fast layered elastic response program for the analysis of flexible pavement structures
    Open this publication in new window or tab >>Fast layered elastic response program for the analysis of flexible pavement structures
    2013 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 14, no 1, p. 196-210Article in journal (Refereed) Published
    Abstract [en]

    One of the key components in analysing pavement structural behaviour is the response model which is used to estimate the stresses, strains and displacements of the pavement structure subjected to the existing traffic, taking into account the material properties and prevailing environmental conditions. Multilayer elastic theory (MLET) is often preferred over other methods such as the finite element method, due to its computational performance for repeated applications. A new elastic response analysis program has been developed based on the Burmister MLET theory to calculate the response of flexible pavement structures. In the development of the program, the time-consuming part of MLET processes was optimised. To improve the convergence and accuracy of responses in the vicinity of the surface of the top layer, an approach based on Richardson's extrapolation was employed. Moreover, an iterative approach to model stress dependency of unbound granular materials was incorporated. A comprehensive comparison of the program with two frequently used programs demonstrated an excellent agreement and improved performance.

    Place, publisher, year, edition, pages
    Taylor & Francis Group, 2013
    Keywords
    Elasticity, Flexible pavement, Model (not math)
    National Category
    Civil Engineering
    Research subject
    Road: Highway design, Road: Surfacing
    Identifiers
    urn:nbn:se:vti:diva-6944 (URN)10.1080/14680629.2012.757558 (DOI)
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2017-12-05Bibliographically approved
    4. Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications
    Open this publication in new window or tab >>Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications
    2015 (English)In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, no 6, p. 488-501Article in journal (Refereed) Published
    Abstract [en]

     Heavy traffic axle load spectrum (ALS) is  one of the key inputs for mechanistic-empirical analysis and design of pavement structures. Frequently, the entire ALS is aggregated into Equivalent Number of Single Axle Loads (ESAL) or assumed to have Constant Contact  Area  (CCA)  or  Constant  Contact  Pressure  (CCP).  These characterizations affect the accuracy and computational performance of the pavement analysis. The objective of this study was to evaluate these  characterizations  based  on  predicted  performances  to  rutting and fatigue cracking of several pavement structures subjected to ALS data collected from 12 Bridge-Weigh-In-Motion stations. The results indicated  that  for  layers  below  the  top  25  cm,  all  characterizations produced similar values of predicted rutting. However, for the top 25 cm, the methods differed in the predicted performances to rutting and fatigue cracking. Furthermore an improvement to the CCA approach was proposed that enhanced the accuracy while maintaining the same level of computational performance.

    Place, publisher, year, edition, pages
    Taylor & Francis Group, 2015
    Keywords
    Axle load, Heavy vehicle, Pavement design, Rutting, Cracking, Prediction, Accuracy
    National Category
    Infrastructure Engineering
    Research subject
    30 Road: Highway design, 32 Road: Pavement design
    Identifiers
    urn:nbn:se:vti:diva-6945 (URN)10.1080/10298436.2014.943131 (DOI)000354458200003 ()2-s2.0-84929283717 (Scopus ID)
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2017-12-05Bibliographically approved
    5. Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement test
    Open this publication in new window or tab >>Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement test
    (English)Manuscript (preprint) (Other academic)
    Keywords
    Viscoelasticity, Full scale, Flexible pavement, Test, Performance, Deformation, Model (not math), Rutting (wheel)
    National Category
    Civil Engineering
    Research subject
    30 Road: Highway design, 32 Road: Pavement design
    Identifiers
    urn:nbn:se:vti:diva-6947 (URN)
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2016-01-11Bibliographically approved
    6. Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement tests
    Open this publication in new window or tab >>Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement tests
    (English)Manuscript (preprint) (Other academic)
    Keywords
    Rutting, Deformation, Bituminous mixture, Flexible pavement, Mathematical model, Full scale, Test
    National Category
    Civil Engineering
    Research subject
    30 Road: Highway design, 32 Road: Pavement design
    Identifiers
    urn:nbn:se:vti:diva-6949 (URN)
    Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2016-01-25Bibliographically approved
  • 5.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Biligiri, Krishna Prapoorna
    Department of Civil Engineering Indian Institute of Technology Kharagpur .
    Hakim, Hassan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    An Algorithm to Estimate Rational Values of Phase Angles and Moduli of Asphalt Mixtures2013In: International Journal of Pavement Research and Technology (IJPRT), ISSN ISSN 1997-1400, Vol. 6, no 6, p. 745-754Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to develop and evaluate an algorithm based on Fast Fourier Transform (FFT) that can calculate rational values of phase angle (f) and moduli of the variants of asphalt mixtures for the data obtained from the different frequency sweep tests. f and moduli for ten different asphalt mixtures resulting in over 690 data points collected from both USA and Sweden were computed using FFT. Theoretical observations revealed that there were significant differences for f between FFT and other methods to the order of 10-50%; however, there was no difference in moduli estimates for any mix and was independent of the test. Precisely, the FFT method produced rational f for mixtures that deviate from conventional mixture properties. Furthermore, statistical comparisons corroborated the predicted f estimates indicative of significant differences between the analysis techniques; but, the moduli were unaffected by the analysis methods. The study successfully illustrated the FFT technique, a user-friendly analytical procedure that can obviate the errors in the rational estimation of the acutely sensitive viscoelastic parameters.

  • 6.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, no 6, p. 488-501Article in journal (Refereed)
    Abstract [en]

     Heavy traffic axle load spectrum (ALS) is  one of the key inputs for mechanistic-empirical analysis and design of pavement structures. Frequently, the entire ALS is aggregated into Equivalent Number of Single Axle Loads (ESAL) or assumed to have Constant Contact  Area  (CCA)  or  Constant  Contact  Pressure  (CCP).  These characterizations affect the accuracy and computational performance of the pavement analysis. The objective of this study was to evaluate these  characterizations  based  on  predicted  performances  to  rutting and fatigue cracking of several pavement structures subjected to ALS data collected from 12 Bridge-Weigh-In-Motion stations. The results indicated  that  for  layers  below  the  top  25  cm,  all  characterizations produced similar values of predicted rutting. However, for the top 25 cm, the methods differed in the predicted performances to rutting and fatigue cracking. Furthermore an improvement to the CCA approach was proposed that enhanced the accuracy while maintaining the same level of computational performance.

  • 7.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of a permanent deformation model for asphalt concrete mixtures using extra-large wheel-tracking and heavy vehicle simulator tests2015In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, no 1, p. 154-171Article in journal (Refereed)
    Abstract [en]

    This paper evaluates a mechanistic–empirical permanent strain model for asphalt concrete mixtures. The evaluation was carried out based on two different types of tests: an extra-large wheel-tracking (ELWT) test and a full-scale accelerated pavement test using a heavy vehicle simulator (HVS). Asphalt slabs from three different types of asphalt mixtures were prepared for the ELWT test and tested at several pavement temperatures and tyre inflation pressures. Lateral wandering was also incorporated.

    The measured permanent deformations in the asphalt slabs were thereafter modelled using the permanent strain model from the US Mechanistic-Empirical Pavement Design Guide and model parameters were estimated for the three types of mixes. For validation, data from an HVS tested pavement structure consisting of the same asphalt mixtures as those tested using the ELWT were used. A set of calibration factors for the three mixtures were therefore obtained between the two tests. In all cases, the calibration factors were within ±20% from unity. Differences in geometry, scale, wheel loading configuration as well as the speed of loading between the two test devices could be the possible reasons for the differences in observed calibration factors.

  • 8.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement testsManuscript (preprint) (Other academic)
  • 9.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests2013In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 14, no 1, p. 178-195Article in journal (Refereed)
    Abstract [en]

    Mechanistic-empirical (M-E) pavement design methods have become the focus of modern pavement design procedure. One of the main distresses that M-E design methods attempt to control is permanent deformation (rutting). The objective of this paper is to evaluate three M-E permanent deformation models for unbound granular materials, one from the US M-E pavement design guide and two other relatively new models. Two series of heavy vehicle simulator (HVS) tests with three different types of base material were used for this purpose. The permanent deformation, wheel loading, pavement temperature, and other material properties were continuously controlled during the HVS tests. Asphalt concrete layers were considered as linear elastic where stress-dependent behaviour of unbound materials was considered when computing responses for the M-E permanent deformation models with a nonlinear elastic response model. Traffic wandering was also accounted for in modelling the traffic by assuming it was normally distributed and a time-hardening approach was applied to add together the permanent deformation contributions from different stress levels. The measured and predicted permanent deformations are in general in good agreement with only small discrepancies between the models. Model parameters were also estimated for three different types of material.

  • 10.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Mechanistic modelling of HVS flexible pavement structure2012In: EPAM 2012: Malmö, Sweden, 5–7 September: 4th European pavement and asset management conference, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 13Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    A response model to be employed in a mechanistic-empirical pavement performance prediction model based on multilayer elastic theory has been developed. An iterative approach using a method of successive over-relaxation of stress dependency model is used to account for the nonlinear behaviour of unbound materials. Asphalt and subgrade materials are assumed as linear elastic. The response model is verified using heavy vehicle simulator (HVS) response measurements made under variety of wheel load configurations and at different pavement temperatures. The permanent deformation behaviours of the HVS structure is also modelled using mechanistic empirical approach and by employing permanent deformation prediction models. A time hardening approach has been applied to combine permanent deformation contributions from stress levels of different magnitude. The response model outputs and the predicted permanent deformations are in general in good agreement with the measurements.

  • 11.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements2012In: Advances in Pavement Design Through Full-Scale Accelerated Pavement Testing / [ed] Jones, Harvey, Mateos & Al-Qadi, London: Taylor & Francis Group, 2012, p. 493-503Conference paper (Refereed)
    Abstract [en]

     A response model to be employed in a mechanistic-empirical pavement performance predictionmodel based on multilayer elastic theory has been developed. An iterative approach using a method of successiveover-relaxation of a stress dependency model is used to account for the nonlinear behavior of unbound materials. Asphalt and subgrade materials are assumed to be linear elastic. The response model was verified against two series of Heavy Vehicle Simulator (HVS) response measurements made under a variety of wheel loadconfigurations and at different pavement temperatures. A comparison with Falling Weight Deflectometer (FWD)data was also carried out. The model was subsequently used to predict permanent deformation from the HVS testing using simple work hardening models. A time hardening approach has been adopted to combine permanentdeformation contributions from stress levels of different magnitude.The response model outputs and the predictedpermanent deformations were generally in good agreement with the measurements.

  • 12.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Numerical validation of viscoelastic responses of a pavement structure in a full-scale accelerated pavement test2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed)
    Abstract [en]

    This paper demonstrates the application of a generalised layered linear viscoelastic (LVE) analysis for estimating the structural response of flexible pavements. A comparison of the direct layered viscoelastic responses with approximate solutions based on the linear elastic (LE) and LVE collocation methods was also carried out. The different approaches were implemented by extending a layered elastic program with an improved computational performance. The LE and LVE collocation methods were further extended for analysis of pavements under moving loads.

    The methods were illustrated by analysing a pavement structure subjected to moving wheel loads of 30, 50, 60 and 80 kN using a Heavy Vehicle Simulator (HVS). The various responses (stresses and strains) in the pavement, at pavement temperatures of 0, 10 and 20°C, were measured using various types of sensors installed in the structure. It was shown that the approximated LVE solution based on the LE collocation method agreed very well with the measurements and is computationally the least expensive.

  • 13.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement testManuscript (preprint) (Other academic)
  • 14.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Viscoelastic Response Modelling of a Pavement under Moving Load2016In: Transportation Research Procedia, 2016, Vol. 14, p. 748-757Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates the application of a generalized layered linear viscoelastic (LVE) analysis for estimating flexible pavements' structural response. The procedure is based on the Multi-Layered Elastic Theory (MLET) and the elastic-viscoelastic correspondence principle using a numerical inverse Laplace transform. A comparison of the direct layered viscoelastic responses with approximate solutions based on the elastic collocation method was also carried out. Furthermore, it is proposed to use the collocation method using LVE solutions at selected time durations in order to improve the accuracy of the elastic collocation method. The LVE collocation method was further extended for analysis of moving loads. The method was illustrated by analysing a pavement structure subjected to moving wheel loads of 30, 50, 60 and 80 kN using a Heavy Vehicle Simulator (HVS). The various responses (stresses and strains) in the pavement, at different pavement temperatures, were measured using various types of sensors installed in the structure. The LVE calculations agreed very well with the measurements.

  • 15.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of tire types and configurations on responses of a thin pavement structure2018In: Advances in Materials and Pavement Performance Prediction, London: CRC Press , 2018Conference paper (Refereed)
  • 16.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lu, Xiaohu
    Nynäs AB.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Pavement performance follow-up and evaluation of polymer-modified test sections2018In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Between 2003 and 2006, a test road consisting of several conventional and polymer-modified structures was built on a motorway. Different combinations of styrene–butadiene–styrene (SBS) and ethyl vinyl acetate (EVA) polymer-modified binders were used. The test structures have been in service since then and have been monitored for over 9 years. The resistance of the different types of asphalt concrete mixes to rutting and cracking was measured and predicted. The impact of ageing on the mixes was also evaluated. Although all the sections are in good condition after 9 years of traffic, the predicted differences between the test sections based on the PEDRO (Permanent Deformation of asphalt concrete layers for Roads) approach and laboratory evaluations are noticeable. Lateral wander and transverse profile measurements indicated that studded winter tyre wear contributed to most of the rutting compared to permanent deformation due to heavy traffic. The unmodified mixes exhibited considerable ageing and the SBS-modified mixes were least affected by ageing. Furthermore, the SBS-modified base mix produced significantly better fatigue resistance than the conventional base mix. However, further investigations of the relationships between bitumen and mix properties and further follow-ups of the test sections are recommended to validate the findings.

  • 17.
    Alfredsson, Magnus
    et al.
    NCC.
    Karlsson, Robert
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Sjögren, Leif
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Hintze, Staffan
    NCC.
    Johansson, Bo
    NCC.
    Lundström, Robert
    NCC.
    Winnerholt, Tomas
    Trafikverket.
    Funktionskriterier för vägkonstruktioner: Förstudie2010Report (Other academic)
    Abstract [sv]

    Det projekt som här rapporteras har som syfte att identifiera och beskriva de svårigheter och möjligheter som totalentreprenader medför, respektive erbjuder, för alla parter. Målet är att utveckla totalentreprenader på ett sådant sätt att branschens effektivitet ökas. Denna rapport är en förstudie där det studerats vilka krav som byggherren ska ställa på utföraren av en vägkonstruktion i en totalentreprenad med funktionsansvar och hur utföraren ska verifiera kraven. Arbetet har genomförts med medlemmar från olika aktörer i branschen och omfattat främst litteraturstudier och intervjuer. Kunskaper och erfarenheter har sammanställts och analyserats för att slutligen kondenseras ned till ett antal förslag till fortsatt arbete.

    Förstudien har pekat ut ett antal områden som viktiga för att påskynda framtida utveckling av totalentreprenader:

    Terminologi – idag råder viss begreppsförvirring

    Analys av funktionella krav i tidigare projekt

    Trafikantkrav

    Miljökrav

    Utveckling av funktionella krav i samverkan

    Väghållarekonomi

    Regelbetingade begränsningar av funktionella krav

    Uppföljning och underlättande av erfarenhetsackumulering

    Implementering av nya mått och mätmetoder

  • 18.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Driving Simulation and Visualization.
    Lidström, Mats
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Rosberg, Tomas
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Framtagning av loktågsmodell för VTI:s tågsimulator2017Report (Other academic)
    Abstract [en]

    Allowing higher speeds for freight trains would provide opportunities for a higher prioritization in the traffic flow by rail traffic management, which in itself is a capacity gain and should generate better flows and higher capacity on the Swedish rail network, especially on the major railways. Simulators are an effective and safe way to investigate the effects of changes in both driver behavior and capacity.

    The purpose of this project was to create capacity-enhancing opportunities and actions by developing a freight train simulator and investigating its possible application areas. The aim of the project was to provide a freight train simulator, consisting of a locomotive and a number of wagons, which can be used in studies to increase capacity through, for example, optimized speed, and thus changing braking profiles, for long trains. The project has delivered knowledge of new test methods, a freight train simulator and a software platform for further testing.

    The project was conducted in three successive stages. In the first phase, a pilot study was carried out with drivers, operators and problem owners, who gave the researchers an understanding of the driving environment. In addition, some of the data needed for the development of the freight train simulator was collected. In the second phase, a freight train (software and hardware) model was developed. Stage three was a validation study together with drivers.

    A Traxx model driver console was purchased from a German manufacturer. The vehicle model was developed from a single unit, Regina type (motorcar train), into a combination of several units. The train in the simulator consists of one or more locomotives and a number of wagons with a total length of up to 750 meters. A locomotive of Traxx model is used. For each device, locomotive and wagon, data is required: length, weight, load, brake, roll and air resistance. In addition, information about noise, driving, braking (re-electrical braking and conventional pneumatic brake) (P-brake), cab equipment and more are added. Currently, the track between Falköping - Jönköping - Forserum is modelled and will be used for ATC trains. The model is configurable using combinations of a locomotive (Traxx) and, currently, four different types of wagons. These can be linked in different combinations.

    Some applications that were discussed at the start of the project were, on the one side, those that could naturally be linked to longer and heavier trains, and, on the other, the ideas that arose because of the equipment purchased. At the Transport Administration winter meeting, a workshop was conducted where further uses were discussed. Among these are applications within education, energy efficient driving or design. Education and certain types of studies could be performed with the existing locomotive model, while others require either validation of parameters or some further development of the model.

    The project has provided knowledge of new test methods, this research report and a product in the form of a freight train simulator and software platform for further testing. The project has also delivered a national resource of simulator software. The software provides for cost-effective testing activities in the freight train domain. A freight train simulator has been developed, which will be valuable as a demonstration tool as well as a platform for training,

  • 19.
    Andersson, Arne
    et al.
    AB Previa/ARA miljö.
    Jacobson, Torbjörn
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Persson, Bengt-Olle
    Peab Asfalt.
    Tillsatsmedel i asfalt: påverkan på arbetsmiljö och omgivning (2006-02-06). Slutrapport2006Report (Other academic)
    Abstract [sv]

    Vissa tillsatsmedel upplevs idag som besvärliga för arbetsmiljön vid tillverkning och utläggning av asfaltmassa. Vidstående projekt som finansierats av SBUF och Peab Asfalt AB syftar till att ta fram relevanta fakta om tillsatsmedel och dess hälso- och miljöproblem. Projektet har dels inriktats som en förstudie av vad som hitintills har gjorts inom asfaltmiljöområdet både i Sverige och i utlandet, dels kompletterande fältmätningar vid asfaltläggning av polymermodifierad asfalt. Studien har utförts i samarbete mellan Peab Asfalt AB, VTI och Previa/ARA-miljö.

  • 20.
    Andrén, Peter
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Fyrhjulsmodeller för bestämning av vägojämnhet: dokumentation av verksamhet på VTI 2002-–20112012Report (Other academic)
    Abstract [en]

    In Sweden, longitudinal roughness has been more or less synonymous with the International Roughness Index (IRI). IRI is calculated from a longitudinal profile, and describes the accumulated movement between the wheel and chassis on a quarter-car model. The result is given as this movement divided with the traveled length. In Sweden, the unit millimeters per mere is normally used. The IRI-model is only affected by movements in the vertical direction, and the speed is fixed to 80 km/h. This report presents the work to make a full-car model, with the aim to produce a more realistic view of the movements of a vehicle traveling on a normal road. The benefits with a more realistic vehicle model is that indices with a higher correlation to drivers’ and passengers’ experiences can be made. It should be mentioned that a relatively high correlation between IRI and drivers’ estimates road condition has been shown. A FullCar model should, however, give more detailed information about the effect of the road surface on the vehicle. A truck model could, for example, be used to find sections with a dangerous cross fall. A realistic vehicle model could also be used in studies concerning the deterioration of roads, as the road is partly worn by wheel abrasions and partly deformed by contact forces. A simple model could simulate hundreds of thousands of vehicle passages in only a few minutes.

  • 21.
    Andrén, Peter
    et al.
    Datamani.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Prognosmodeller för tillståndsmått i Trafikverkets Pavement Management System: IRI och spårdjup2014Report (Other academic)
    Abstract [en]

    In Sweden, the road surface condition is assessed regularly with laser-based profilographs. This has been done since 1987. All roads are, for financial reasons, not assessed every year, but one way to describe the condition of the entire road network is to work with models. The purpose of these assessments is to provide the Swedish Transport Administration’s Pavement Management System (PMS) with data. The main uses of the PMS are: • To provide a description of the overall road condition and its changes to determine if the selected operation and maintenance strategies are successful, and if an acceptable road standard can be offered. • Support the maintenance planning (prioritization and selection of sections for maintenance). • Support for the choice of maintenance method. • Monitoring of performance of construction or maintenance, for example, functional related contracts. • To support research. The Swedish Transport Administration needs a complete description of the road condition in order to demonstrate to the government and parliament how the mission to maintain the roads is achieved. One way to describe the condition of the entire road network is to work with models that forecast the condition the years when measurements are missing. In the choice between using a global or local model to describe the state of development for IRI (International Roughness Index) and rut depth on individual 100-meter segments, the present report shows that a local model is preferred. The coefficient of determination is not high enough in a global model. Also, the researchers cannot see any consequent pattern in the regression coefficients for the explanatory variables we have tried.

  • 22.
    Antonson, Hans
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Mobility, actors and planning processes.
    Ahlström, Christer
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Wiklund, Mats
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Mårdh, Selina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Crash Barriers and Driver Behavior: A Simulator Study2013In: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 14, no 8, p. 874-880Article in journal (Refereed)
    Abstract [en]

    Objective: The study examines how drivers experience a conventional W-beam guardrail (metal crash barrier) along both sides of narrow versus wider roads (single carriageway with 2 lanes) in terms of stress, feelings, and driving patterns and whether subjective experience concurs with the actual driving patterns captured by the quantitative data.

    Methods: The study used different methods to capture data, including the VTI Driving Simulator III (speed and lateral vehicle position) in conjunction with electrocardiogram (ECG) data on heart rate variability (HRV) and questionnaires (oral during driving and written after driving). Eighteen participants-8 men and 10 women-were recruited for the simulator study and the simulator road section was 10 km long.

    Results: Driving speeds increased slightly on the wider road and on the road with a crash barrier, and the lateral driving position was nearer to the road center on the narrower road and on the road with a crash barrier. The HRV data did not indicate that participants experienced greater stress due to road width or due to the presence of a crash barrier. Participant experience captured in the oral questionnaires suggested that road width did not affect driver stress or driving patterns; however, the written questionnaire results supported the simulator data, indicating that a wider road led to increased speed. None of the participants felt that crash barriers made them feel calmer.

    Conclusions: We believe that there is a possibility that the increased speed on roads with crash barriers may be explained by drivers’ sense of increased security. This study demonstrates that an experimental design including experience-based data captured using both a simulator and questionnaires is productive. It also demonstrates that driving simulators can be used to study road features such as crash barriers. It seems more than likely that features such as street lamps, signs, and landscape objects could be tested in this way. © 2013 Copyright Taylor and Francis Group, LLC.

  • 23.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholms universitet, Karolinska Institutet.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ihlström, Jonas
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Ingre, Michael
    Stockholms universitet.
    Radun, Igor
    University of Helsinki.
    Söderström, Beatrice
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Bussförares arbetstider kopplat till trötthet2014Report (Other academic)
    Abstract [en]

    Bus drivers often have irregular working hours and their work involve high levels of stress. These factors can lead to severe fatigue and the purpose of this study is to highlight how the working hours affect sleep, stress, fatigue and driving performance. The project includes four studies: questionnaire, sleep diaries and actigraphy, analyze of rosters and an experiment on real road with bus drivers. The hypotheses were that early morning shift, split shifts, long working hours and short hours of rest between shifts contribute to sleepiness, stress, fatigue and impaired driving performance, which together can result in increased safety. The overall results support these hypotheses. Generally, sleepiness and fatigue while driving are perceived as problems because drivers connect those factors with impaired driving performance, which increases the risk of incidents and accidents. In total 45 percent of all drivers had trouble at least twice a month to stay awake while driving and 19 percent had over the past decade been involved in an incident due fatigue. The experiment with split shift driving support these findings. The report concludes with a list of suggestions.

  • 24.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Söderström, Beatrice
    Swedish National Road and Transport Research Institute, Infrastructure, Crash safety.
    Utvärdering av effekten av förstärkt information vid övergångsställe (FIVÖ)2010Report (Other academic)
    Abstract [sv]

    Förstärkt information vid övergångsställe, så kallade FIVÖ-system, är effektivt i termer av att öka fotgängares upplevelse av säkerhet och trygghet vid passage av övergångsstället. Syftet med föreliggande studie var att utvärdera effektiviteten av FIVÖ-systemen samt att fånga fotgängares, cyklisters och förbipasserande trafikanters uppfattning om de klassiska FIVÖ-systemen.

    Studien omfattar en första genomgång av olyckor vid övergångsställen, hastighetsmätningar vid ett urval av platser samt intervjuer med fotgängare, cyklister och bilister som passerar FIVÖ-system. Resultaten visar att flest olyckor vid övergångsställen sker i tättbebyggt område i anslutning till korsningar på vägar där hastighetsbegränsningen är 50 kilometer i timmen. Detta speglar framför allt att det är där det finns övergångsställen. För urvalet av mätplatser visar resultaten av hastighetsmätningarna en signifikant lägre hastighet (~ 2,2 km/h) då FIVÖ-systemet var aktivt jämfört med då det inte finns ett system. Vidare visar resultaten att såväl fotgängare som cyklister upplever att systemen bidrar till att de är säkrare, känner sig trygga och att förbipasserande i större utsträckning stannar och släpper dem före. Bilisterna upplever att systemet bidrar till att de lättare kan upptäcka fotgängare och cyklister vid övergångsstället. Det finns dock en del utvecklingspotential avseende synbarheten. Såväl bilister som fotgängare och cyklister anser att de ljus som används vid testade FIVÖ-system kan förbättras och förstärkas.

  • 25.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sörensen, Harry
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Externt och internt buller samt vibrationer vid körning på sinusräfflor2010Report (Other academic)
    Abstract [sv]

    Studien omfattar en jämförelse av ljudnivåer och vibrationer i fordon vid körning på två typer av räffelutformning, en konventionellt fräst räffla och en sinusformad räffla.

    Mätningar av interna och externa ljudnivåer samt vibrationer i chassi och säte har skett vid körning på fyra sträckor; en sträcka med vanlig fräst räffla (konventionell), vid denna har dels en äldre räffla ingått, dels en nyfräst räffla. Vidare har tre sträckor med sinusformade räfflor ingått.

  • 26.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Energieffektiv vinterväghållning: val av driftstandardklass2013Conference paper (Other academic)
  • 27.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Kostnader för fotgängarskador vs vinterväghållningskostnader2013Conference paper (Other academic)
  • 28.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Krav för att förhindra fallolyckor: tekniska egenskapskrav för gator och vägar2017Report (Other academic)
    Abstract [en]

    Since injured pedestrians due to falling contributes to high costs for society, therefore the attribute requirements on a road surface is of great importance for safety. The requirements shall be appropriate for all who are on the surface, this applies to both vehicles, cyclists and pedestrians. This report summarises recent accident studies and the prevailing rules regarding the construction of spaces for pedestrians.

    In addition to these compilations an analysis is done of how common it is that people fall due to, for example, uneven surfaces, kerb-stones or stumble. In 38 percent of the reported accidents that occurred between 2008 and 2015 (82,559), the victims said that the accident happened on a footpath/pavement. To give a good picture of how many accidents that may occur due to surface and paving was 4,443 accidents filtered out, and all the descriptions were read and divided into 12 various categories. The most common reason to a person being injured, according to themselves, was unevenness, holes and pits, level differences or related to the stone/tile surface. The social-economic cost for these 4,443 accidents was in average 845 thousand SEK.

  • 29.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    RSI: Road Status Information2013Conference paper (Other academic)
  • 30.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sträckprognoser E62013Report (Other academic)
    Abstract [en]

    Road stretch forecasting is a method for forecasting the weather situations or road conditions, especially slipperiness. This project has been a start on implementing the road stretch forecasting technique on Swedish roads. Road stretch forecasting is already implemented in several parts of the world including Norway and the Czech Republic and is a method for forecasting the weather situations or road conditions on the stretches between the existing Road Weather Information System outstations (RWIS). RWIS outstations are located all over Sweden and mainly in places where there is a high probability of slipperiness. But if the area around the station is changed, for example modifications of the vegetation, the conditions can be changed compared to the original mapping of the road. This leads to a high probability for extreme points in road stretches in between the RWIS outstations. To make a model that describes the road, it is necessary to make a thermal mapping and an analysis of the topoclimate to know the variations in temperature, altitude, shading etcetera, along the road. Then the road is divided into segments representing the different variations of the road. The model calculates the forecast for the road surface temperatures and road conditions, the modelled values are compared and adjusted with the measured temperatures from the thermal mapping. In conclusion, the results regarding this road stretch along E6 show good congruence between the modelled values and the measured temperatures.

  • 31.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sustainability and climate change considerations in winter maintenance2015Conference paper (Other academic)
  • 32.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Tekniker och metoder för mer energieffektiv vinterväghållning2011Report (Other academic)
    Abstract [en]

    One important question in winter road maintenance is: How can we make winter road maintenance more energy efficient? There are several factors that can affect how, when and where the winter road maintenance is performed.

    A RWIS outstation (Road Weather Information System) measures the road weather on the road and close to the road, it measures many parameters, such as road surface temperature, air temperature, relative humidity, precipitation type and amount, wind speed and direction. Measured parameters together with weather forecasts make it possible to determine when and where the action is needed. Thereafter it is time to make a route planning to ensure that the correct action is done on the right place at the right time, and with the best suited equipment for the winter road maintenance.

    Spreading of salt/sand could be more efficient by using different computer programs that calculate the needed amount. Also the location of the salt/sand storage affects the driving distances i.e. the fuel consumption.

    One of the factors that account for the greatest uncertainty in terms of winter road maintenance is the weather. An area that has a need for more research is how future climate changes will affect the winter maintenance.

  • 33.
    Arvidsson, Anna K.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Tema Vintermodell: kalibrering och vidareutveckling av Vintermodellen2014Report (Other academic)
    Abstract [en]

    The project “Winter Model” started at the beginning of the 2000s. The idea was to try and predict consequences of different winter maintenance strategies so that socio-economic costs could be calculated. Using the Winter Model programme, developed during the project, it is now possible to calculate and validate the impact of different winter maintenance measures have on road users, road authorities and local communities. This report contains results of the first complete Winter Model calculations using existing conditions. The report also contains an account of further developments made in connection with this study within the Winter Model. In order to determine what effect changes to road classification standards have on socio-economic costs, the report includes seven comparisons of different application runs. Road classification standards determine how much snow should fall before an action is initiated and/or how long it should take until the action is completed.

  • 34.
    Arvidsson, Anna K.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Tema Vintermodell: val av standardklass på vinterväghållning med hänsyn till energieffektivitet2015Report (Other academic)
    Abstract [en]

    The Winter Model has been developed within a project called The Winter Model. The aim of the project, which started in the early 2000s, was to assess social and economic consequences of different winter maintenance strategies for road users, road authorities and local communities. The aim of this study was to calculate the change in fuel consumption when the winter maintenance classification standard is lowered on the road i.e. response times and start criterion is increased. Within this project, the fuel consumption model was refined and can now take into account how fuel consumption is affected by the amount of water or snow in the ruts on the road. During the project, six scenario runs were carried out for a 100 km long road section located in Sweden’s central climatic zone. Weather data was obtained from the winter season 2006–2007. Winter maintenance classification standards, and traffic flow volumes were varied during the scenario runs. In one scenario run, the winter maintenance classification standard was lowered from Standard Class 1 to Standard Class 2. This increased the allowable time to carry out the maintenance action from 2 hours to 3 hours – applicable to a Standard Class 1 road, salted, and with a traffic volume of 16,000 vehicles. Comparisons indicate a 1,100 litre reduction in total fuel consumption and maintenance costs was reduced by 5%.

  • 35.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    The Winter Model: A new way to calculate socio-economic costs depending on winter maintenance strategy2017In: Cold Regions Science and Technology, ISSN 0165-232X, E-ISSN 1872-7441, Vol. 136, p. 30-36Article in journal (Refereed)
    Abstract [en]

    The project “Winter Model” started at the beginning of the 2000s. The idea was to try and predict the consequences of different winter maintenance strategies and to calculate the associated socio-economic costs. It is now possible to calculate and validate the impact that different winter maintenance measures have on road users, road authorities and local communities.

    This paper contains results of the first complete Winter Model calculations using existing conditions. Comparisons with different road classification standards have been carried out in order to determine the effect they have on socio-economic costs. Road classification standards dictate how much snow should fall before a maintenance action is initiated and how long it should take until the action is completed. Socio-economic costs increased for all comparisons when reductions in the classification standard were applied. As an example of how costs can vary: the scenario is a salted road using a combined plough and salt spreader where the allowed time to complete the action is 4 h that is changed to an unsalted road with an allowed time to complete the action of 5 h. Both scenarios have an action start criteria of 2 cm deep snow, and an annual average daily traffic flow of 2000.

    Comparison results show that the change from salted to unsalted road saves the most cost due to a reduction in salt use and required actions. However, the increased time to complete the action will result in slightly longer travel times and accident costs will increase by 24.2%. The extended action hour affect fuel consumption in a positive way, for example, consumption decreases slightly due to driving more often at lower speeds on unclear roads. By lowering the road classification standard like in this example, total socio-economic costs increased by 3.5%.

  • 36.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    The Winter Model: Socio-Economic Cost Calculations for the Future2016In: Routes/Roads, ISSN 0004-556X, no 369, p. 48-55Article in journal (Refereed)
  • 37.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    The winter model: Socio-economic cost calculations for the future2015In: Proceedings of 25th World Road Congress / [ed] PIARC, 2015Conference paper (Other academic)
    Abstract [en]

    The project “Winter Model” started at the beginning of the 2000s. The idea was to try and predict the consequences of different winter maintenance strategies and to calculate the associated socio-economic costs. It is now possible to calculate and validate the impact that different winter maintenance measures have on road users, road authorities and local communities. This paper contains results of the first complete Winter Model calculations using existing conditions. Comparisons with different road classification standards have been carried out in order to determine the effect they have on socio-economic costs. Road classification standards dictate how much snow should fall before a maintenance action is initiated and how long it should take until the action is completed. Socio-economic costs increased for all comparisons when reductions in the classification standard were applied. Accident costs consistently accounted for the largest cost increases in all of the comparisons. Current climate change impact scenarios for northern Europe predict an increase in temperature and precipitation, especially during the winter seasons. Some attempts have been made to use the Winter Model for comparisons between different winters, for example variations in weather patterns. These attempts tried to calculate winter maintenance and socio-economic costs for future winter seasons.

  • 38.
    Arvidsson, Anna K
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Vintermodellen 2018: uppdatering av Olycksmodellen inklusive uppdateringar av värderingar till ASEK 6.12018Report (Other academic)
    Abstract [en]

    This report is a compilation of the work done of recalculating the relations/connections for accident risks and their distribution on different winter road conditions in different climate zones. These accident risks are based on accidents having occurred between the years 2007 and 2017. In this project, an update of the accident assessments has been made according to ASEK 6.1 (analysis method and socioeconomic calculation values for the transport sector) Due to this change, the Swedish Transport Administration has changed the valuation of road traffic accidents with accident consequences according to Strada (Swedish Traffic Accident Data Acquisition), instead of consequences as reported by police reports. The new update of the Accident Model has updated accident risks, accident distributions and accident consequences and seems to be realistic and the program is working in a correct way.

  • 39.
    Arvidsson, Anna K.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Winter Management Systems…: eller finns det andra versioner av Vintermodellen? En översikt över befintliga system2014Report (Other academic)
    Abstract [en]

    VTI has developed a model called the Winter Model, a strategic tool to make calculations for the winter road maintenance during the whole winter season and how this affects the societies costs. This report contains a summary of other models used in this area. The report mostly contains brief explanations of some of the existing tactical decision support systems. No strategic models which is used as tools for follow-up on consequences depending on actions taken on the road, level of winter service, and on how a different winter seasons climate affects the economics, could be found. Most countries have developed their own tactical decision support system. These systems are in many cases very similar, and they are generally used for the decision of the best maintenance activity to perform. The model that reminds the most of the Swedish Winter Model is the American MDSS-model, which has approximately the same incoming data. The largest difference is that it is more used in the daily activities and not as a tool to make calculations for the winter road maintenance during the whole winter season and how this in turn affects the societies costs.

  • 40.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Öberg, Gudrun
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Klimatanpassning av vägkonstruktion, drift och underhåll2012Report (Other academic)
    Abstract [en]

    The global climate change is a reality and affecting society and transport systems. Climate change adaptation of transport systems will make the means of transportation more resilient and decrease the risk and magnitude of disruptions. Generally, climate change adaptations in road construction, operation and maintenance will need relatively large changes, but there is a shortage of the specific knowledge required as to what steps need to be taken, when and where, before measures can actually be implemented. Since climate change effects vary among Sweden's climatic zones, the impact of climate change on the road behavior and longevity is extremely difficult to predict. The need for winter maintenance in Sweden will generally decrease due to the warmer climate. Ploughing frequency will probably decrease as well, but preparedness should not be reduced too much since occasions with more extreme instances will increase. In order to succeed in making the road transport system resilient to climate change, we conclude that there is a need to develop more knowledge about the impact on the road infrastructure system as well as the operation and maintenance of the system including how to adapt through different types of variable and flexible climate adaptation measures and the effects of extreme weather events.

  • 41.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Öberg, Gudrun
    Swedish National Road and Transport Research Institute, Infrastructure.
    The impact of climate change on the use of anti- and de-icing salt in Sweden2012In: Transportation Research Circular: Winter Maintenance and Surface Transportation Weather, 2012, p. -10Conference paper (Refereed)
    Abstract [en]

    The future needs for winter maintenance will probably be influenced by the climate change in different ways in different parts of the world. As Sweden is a country with several climate zones, the influence of climate change on winter maintenance will therefore differ between regions within the country. To understand the influence of climate change on the future needs of salt consumption in winter maintenance, modeled road weather data were calculated in the IRWIN project (a joint research project through ERA-NET ROAD funded by the 6th Framework Program of the European Commission), where climate change scenarios from ECHAM5 (the fifth generation of the European Centre Hamburg Model general circulation model from the Max-Planck Institute for Meteorology) were combined with field data from the road weather information system in Sweden.

    These modeled road weather data were used in project KLIVIN (the study presented here) in three Swedish regions (Gothenburg, Stockholm, and Sundsvall) and was combined with the Swedish winter severity index in order to calculate the trends of future salt needs. In this study the needs of salt for each of the three investigated regions were calculated in 30-year periods between 1970 and 2100. The results show that salt use related to snowfall will decrease in all three regions, while the salt use related to temperature will increase in the northernmost region (Sundsvall) and show a small decrease in the two other regions (Gothenburg and Stockholm).

  • 42.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Bäckström, Andreas
    Svevia.
    Wärme, Mats
    B&M Systemutveckling AB.
    Dynamisk prognosstyrd vintervägdrift: Fas 22018Report (Other academic)
    Abstract [en]

    Unpredictable weather, short time frames and requirements of high quality can make a challenge of the winter road maintenance. The pressure on both operating staff and machine drivers is very high during periods. The road climate can vary greatly within one and the same operating area and there is a need to adjust for these variations to maximise efficiency.

    The project "Dynamic Forecast Controlled Winter Road Maintenance" has been aimed at developing a solution to simplify the handling of data flows from road weather forecasts and simplify decisions for the winter maintenance contractor what actions are needed and where they are needed. This has been done with data from road weather forecast services together with the existing road network in the operating area, the actions have been optimized for the available numbers of vehicles to create dynamic actions for a more productive and sustainable winter road maintenance.

    Two phases of the project have now been completed and the purpose and goal of streamlining operations through interconnected data flows has been achieved. In connection with this, a dynamic forecasting route optimisation product has also been developed. The project showed that using a dynamic forecasting route optimisation, is it possible to carry out the full potential of the decision support systems through automation. The potential of using forecast-based winter road maintenance is great, both for the customers and for the individual operating contractor. The contractor benefits from it in the operational work, improves the working environment and reduces costs. However, environmental impact also decreases, and in the long term, it also reduces the social economic costs of road maintenance. It is important to emphasise that the technology enables the safety factor on the road to not be reduced despite savings of salt and action times.

  • 43.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Wärme, Mats
    B&M System AB.
    Bäckström, Andreas
    Svevia.
    Dynamic Forecast Controlled Road Maintenance2018Conference paper (Refereed)
  • 44.
    Arvidsson, Anna K.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Gustavsson, Torbjörn
    Göteborgs universitet / Klimator.
    Bogren, Jörgen
    Göteborgs universitet / Klimator.
    Nya regler för en effektivare vinterväghållning: En förstudie2013Report (Other academic)
    Abstract [en]

    Current winter maintenance costs are approximately 2 billion SEK per annum, but good monitoring tools to ensure that this money is distributed and used effectively are lacking. The purpose of this study was to develop a basis for new regulations for when action is required to maintain good winter road standards and how payment to the entrepreneurs should be regulated to provide a more efficient winter road maintenance. The Swedish Road Weather Information System (RWIS) was introduced as an aid for winter road maintenance in the late 1970s. The service expanded during the next two decades and today comprises of around 800 stations situated around the Swedish state road network. Measurements include air and road surface temperature, wind direction and speed, and precipitation type and amount. Many of the stations are also equipped with cameras that can be used to assess road surface conditions. Together with weather forecasts, information from RWIS stations is used as the main basis for decision making regarding the need for winter road maintenance. The first step in system improvement is to fully understand how the current system operates. This report summarises the broad outlines of how reporting, regulatory frameworks, and reimbursement models work for winter road maintenance. There are a number of relatively new techniques that could be used to optimise winter road maintenance. These new techniques could help produce a more efficient winter road maintenance programme that reduces the cost to society. The technological developments have moved forward in recent years in a number of areas such as the motor vehicle industry and also in non-contact sensors for measuring friction and road surface temperature. This technology can be used in conjunction with RWIS to give a clear indication of when and where maintenance action is required. This could also provide an opportunity to design a decision support system that could assist road maintenance contractors.

  • 45.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Test av korrektionstjänst för GPS-mottagare vid vägytemätning2012Report (Other academic)
    Abstract [en]

    An important factor in the inventory of the road network condition is to be able to geographically position the measurement data at the right place with sufficient accuracy.

    In March 2012, the correction service EPOS, used to provide an improved positioning, was shut down. By the commission of the Swedish Transport Administration, VTI has evaluated whether the free correction service EGNOS, operated by ESA, is possible to be used instead. The answer is yes. No systematic differences in the position data could be observed when using the old and the new correction service.

  • 46.
    Arvidsson, Anna K.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sjögren, Leif
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Genell, Anders
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Ögren, Mikael
    Göteborgs universitet.
    Åkkvalitet på vinterväg2014Report (Other academic)
    Abstract [en]

    What can be stated in this project is how a winter road is experienced when compared to snow free conditions, primarily with regard to unevenness and noise. Surveys carried out during the project show that it is possible, without too much difficulty, to measure the unevenness of a snow covered road surface. I this report is winter road defined as a snow covered road (around one day after heavy snowfall). Based on survey results, the study shows that the unevenness of section lengths between 0.05 metres and 1.0 metres are most affected by winter road conditions. Unevenness during winter road conditions is approximately five times greater than that experienced during snow free conditions. However, it is impossible to generalise for an entire road network as surface conditions during winter can be extremely variable. It is also possible to see that the surface structure described by the shortest wavelengths investigated, less than 10 millimetres, is smoother on the snow-covered surface. This is one hypothesis and indicates that measurements are reliable. The link between noise and unevenness is related to vehicle speed. The biggest sound difference between winter and summer road conditions, which could be related to the road surface measurements, was at the lower frequency range. Perceived in-car noise levels were between 3 and 6 decibel higher during winter conditions. However, for the higher frequency range the difference in noise levels was opposite - lower levels during winter conditions. A possible explanation for this is that sound may be absorbed by the snow.

  • 47.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Wärme, Mats
    B&M system AB.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Bäckström, Andreas
    Svevia.
    Dynamisk prognosstyrd vintervägdrift: Summering av Fas 12017Report (Other academic)
    Abstract [en]

    The task of the winter maintenance operations is to ensure that the roads are accessible and safe to use. In practice, by means of ploughing, sand and salt spreading, keeping the roads free of snow and ice in accordance with the current requirements. Experience in operational winter management is a shortcoming, which is partly due to the more flexible labour market with short contract periods, but also due to the major retirements that have been in recent years. In order for the winter maintenance contractor to maintain and at the same time increase the productivity, it is essential to develop decision support systems.

    There are today several road weather forecast services that can provide qualified support to decisionmakers in winter road maintenance. As a basis, current weather information from the Swedish RWIS-outstations (Road Weather Information System), which is deployed along the state roads, is used. Some services also use data from sensors in cars. The services provide dynamic road conditions forecasts and in some cases even proposals for actions needed for different road sections. They deliver detailed decision-making prognosis that enable high quality decisions for the correct action in the right time at the right place. Perhaps the main advantage of the forecasts is that they clearly show that only parts of the road network need to be addressed and that the surface temperature forecast, in addition to the forecast of the road surface condition, is important input for determining the needed amount of salt.

    Today’s route optimisation program performs optimisations for the shortest time based on the road owner's road classification, that is based on annual average daily traffic. However, road climate may vary considerably within an operating area, and the need to adjust for these variations in order to achieve an increased resource efficiency, can currently only be corrected manually for resource planning, and usually before the winter season starts.

    The purpose of the project is to provide a more dynamic information to create a more productive winter road maintenance with dynamic road conditions information. Integrating data from a road weather forecast service into existing systems, such as a route guidance driver system, would allow the workforce to work significantly more detailed and dynamically, allowing for significant efficiency gains. In the project, an evaluation of a weather service has also been made with regards to which forecast window is suitable to use in the optimization. The project in this first phase can be described as a first attempt to make the systems working together, validate that it is feasible and that results will be reliable routes for the decisionmakers in winter road maintenance.

    The project has shown that a dynamic forecasting route optimisation for preventative salting can improve the environment by reducing emissions from lorries due to shorter driving distances and reduction of salt usage. The work environment for the maintenance vehicle drivers is enhanced by a higher degree of automation, which means it is less to keep track of, resulting in reduced stress at high performance requirements. Better quality in the winter road maintenance also benefits accessibility for the road users.

  • 48.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    HVS-test för skattning av nedbrytningseffekter från den tunga trafikens belastning: SE14, SE18 och SE202014Report (Other academic)
    Abstract [en]

    This publication describes the aim and outcome of the constructions made to estimate deterioration/degradation of roads from the load of heavy traffic. The purpose was to study three constructions with three different wheel-loads (40 kN, 50 kN and 60 kN which corresponds to axle-loads of 8 tons, 10 tons and 12 tons). To minimize the test matrix the idea was to copy older test constructions tested with the wheel-load 60 kilonewton (kN). The outcome was not to full content, especially did the thinner, older constructions differ in the bearing capacity (static plate loading). For the most modern construction (SE14), with totally of 625 millimetre of super structure including 111 millimetre of asphalt layers, that was compared with SE10 and SE11 the differences was acceptable. The wheel load was 40 kN in 600 000 passes and 50 kN for another 600 000 passes, in total 1.2 million passes. Total rut depth became approximately 6 millimetre. The ”medium” construction (SE18) had a super structure of 349 millimetre including 100 millimetre of asphalt layers and it was compared with SE06. The wheel load was 40 kN in 500 000 passes, 50 kN for 400 000 passes and 60 kN in 300 000 passes, in total 1.2 million passes. Total rut depth became just over 11 millimetre. The thinnest construction (SE20) had a super structure of 310 millimetre including 70 millimetre of asphalt layer and it was compared with SE02. The wheel load was 40 kN in 390 000 passes, 50 kN for 170 000 passes and 60 kN in 190 000 passes, in total 0.75 million passes. Total rut depth became almost 21 millimetre.

  • 49.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jämförande provning – ballast 2015: flisighetsindex, korndensitet och kulkvarn2017Report (Other academic)
    Abstract [en]

    This report shows results, some statistical analysis and precision data for profiency testing (round-robin) performed on three materials of aggregate during 2015. The properties that was determined was Flakiness Index (EN 933-3), particle density (EN 1097-6) and Nordic ball mill (EN 1097-9). The number of participating laboratories were for Flakiness index 58 pcs., for particle density 60 pcs. and for Nordic ball mill 52 pcs.

    There are some scatter of the results which is not surprising. A few of the laboratories show clearly high or low results (for all three materials) for one of the analysis. Generally is the scatter in results varying. E.g. some of the laboratories have a clearly high result for one of the materials, a slightly low result for the second material and are quite close to the average for the third material.

    The standard deviations increase with increase in level of results (average), but not as much. The ratio of standard deviation and average decrease with increase of level.

    The precision data from this round-robin over all matches the levels from the test standards. The tests from this report has often a wider range of results. There is a correlation between reproducibility and level of average. The repeatability has not been calculated because tests actually have been performed as single tests.

    Analysis of background data, like handling, dimensions and type of model, shows that they have none or very little significance.

  • 50.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jämförelse mellan Los Angeles-värde och nedbrytning från hjullast2011Report (Other academic)
    Abstract [en]

    Since 2004 the Swedish Road Administration has had requirements on unbound base layer concerning the resistance to fragmentation, the Los Angeles value. To study how degradation from traffic load is affected by resistance to fragmentation five materials with different Los Angeles values were tested in VTI’s Heavy Vehicle Simulator (HVS).

    The degradation from the wheel load has been recorded by comparing the grain size distribution before and after the HVS test. Some values from the grain size distribution have been used or calculated to easier compare the grading curves with the Los Angeles value, e.g. content of fines (material < 0.063 mm) or the area under the grain size distribution curve.

    There is a clear degradation from the wheel load of the HVS in unbound base layer materials. There is, however, not a clear connection between this degradation and the resistance to fragmentation, Los Angeles value. Therefore it is not possible from this investigation to recommend a new level or category of requirements concerning the resistance to fragmentation on unbound base layer material.

    The most important conclusion is that the method that has been used in this project is working to study the degradation and particle relocation in unbound layers.

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