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Publications (10 of 17) Show all publications
Olstam, J., Johansson, F., Liu, C. & Pereira, I. (2020). An approach for systematic assessment of infrastructure automation readiness from a traffic performance perspective. In: Proceedings of 8th Transport Research Arena TRA 2020: . Paper presented at 8th Transport Research Arena TRA 2020, April 27-30, 2020, Helsinki, Finland. (Conference canceled) (pp. 10).
Open this publication in new window or tab >>An approach for systematic assessment of infrastructure automation readiness from a traffic performance perspective
2020 (English)In: Proceedings of 8th Transport Research Arena TRA 2020, 2020, p. 10-Conference paper, Published paper (Refereed)
Abstract [en]

Road authorities need tools to assess potential impacts on traffic performance due to the introduction of automated vehicles. Extended traffic modelling tools offer possibilities to estimate impacts on traffic performance metrics such as travel time, delay and capacity. However, there are large uncertainties related to the future behavior of automated vehicles, and these need to be carefully handled. The aim of this paper is to present a systematic and sound approach that can be used by road authorities to assess the automation readiness of a specific infrastructure. We present a definition of automation readiness from a traffic performance point of view, and an approach for how to estimate the automation readiness for a specific road design taking the uncertainties in the development of automated vehicles into account. The developed approach is applied to both macroscopic and microscopic use cases, demonstrating the applicability of the approach for automation readiness assessment.

Keywords
Autonomous vehicle, Traffic, Simulation, Mathematical model, Forecast, Variability
National Category
Transport Systems and Logistics
Research subject
20 Road: Traffic engineering, 23 Road: ITS och traffic; 20 Road: Traffic engineering, 25 Road: Traffic theory
Identifiers
urn:nbn:se:vti:diva-15037 (URN)
Conference
8th Transport Research Arena TRA 2020, April 27-30, 2020, Helsinki, Finland. (Conference canceled)
Available from: 2020-03-06 Created: 2020-03-06 Last updated: 2020-04-29Bibliographically approved
Liu, C., Tapani, A., Kristoffersson, I., Rydergren, C. & Jonsson, D. (2020). Development of a large-scale transport model with focus on cycling. Transportation Research Part A: Policy and Practice, 134, 164-183
Open this publication in new window or tab >>Development of a large-scale transport model with focus on cycling
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2020 (English)In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 134, p. 164-183Article in journal (Refereed) Published
Abstract [en]

This study presents a transport model to better model cycling demand. The model improves modelling of cycling in several ways compared to a conventional transport model. First, it uses a detailed bicycle network containing information about existing bicycle infrastructure. Second, generalised cost measures based on different bicycle route choice models are calculated and compared to evaluate how to best represent the impact of bicycle infrastructure in the model. Third, the model utilizes a refined zone system with smaller zones of size 250 m × 250 m. Using these smaller zones, more short-distance tours are included in the model, and these are predominantly walking and cycling trips. Fourth, the model considers cycling also as an access mode choice to public transport. Therefore, the model treats cycling and public transport as both competing and complementary modes. Results show that the model captures detailed individual heterogeneity in cycling demand for different trip purposes. Impacts of bicycle infrastructure, land use characteristics and individual/household socio-demographics are investigated. Detailed individual level travel time and generalised cost are derived for cyclists of different socio-demographics. The result highlights the importance of choosing a good measure of generalised cost, given that different bicycle route choice models result in different effects of bicycle infrastructure. In future applications, the model can be used to evaluate proposed bicycle investments regarding their impact on link flow, bicycle route choice, modal shift and generation of completely new tours. The model can also be a powerful tool in a cost-benefit analysis of bicycle investments.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Transport network, Bicycle, Mathematical model, Cycling infrastructure, Route (itinerary), Choice, Modal choice, Journey purpose, Land use, Journey time, Cost
National Category
Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 113 Road: Cycling, walking and moped transport
Identifiers
urn:nbn:se:vti:diva-15082 (URN)10.1016/j.tra.2020.02.010 (DOI)2-s2.0-85079644007 (Scopus ID)
Available from: 2020-03-09 Created: 2020-03-09 Last updated: 2020-04-29Bibliographically approved
Zhang, C., Campana, P. E., Liu, C., Wang, K. & Yan, J. (2019). Crowdfunding preferences for a sustainable milk product with integrated photovoltaic water pumping system in China. Applied Energy, 255, Article ID 113694.
Open this publication in new window or tab >>Crowdfunding preferences for a sustainable milk product with integrated photovoltaic water pumping system in China
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2019 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 255, article id 113694Article in journal (Refereed) Published
Abstract [en]

This paper studies the role of potential investors in financing renewable energy systems—specifically, relating to crowdfunding as a financing mechanism, with the enhancement of internet and social-media tools. The research question in this study is whether crowdfunding with a novel socio-technical product reward program attracts potential customers to a more sustainable milk product with a specific integrated photovoltaic water pumping (PVWP) system. The particular case study we empirically investigated is product reward crowdfunding in dairy milk production in China. The milk production chain was supplied by PVWP system integration, which generated solar energy both for feed production for dairy cows and for the operation of dairy farms. 48 semi-structured in-depth interviews were conducted between the research team and customers in order to perform qualitative analyses of the determinants of customers’ milk purchase behaviors. In addition, 357 online surveys were collected for quantitative analysis. Binary and ordered probit regressions were employed to use survey date to systematically estimate purchase intention and willingness-to-pay for sustainable milk. Customer behaviors, environmental consciousness, and individual socio-demographic factors were investigated as potential explanatory variables.

This article evaluated key factors which may influence potential customers for crowdfunding, and used a discrete choice model to estimate customers’ willingness-to-pay for reward-based projects. These results could help producers of sustainable milk products to identify potential target groups in China and estimate market demand. This exploratory study could provide a framework with both quantitative and qualitative assessment of crowdfunding for renewable energy systems in a national or international context.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Investment, Production, Agriculture
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
SAB, Qb Managerial economics
Identifiers
urn:nbn:se:vti:diva-14160 (URN)10.1016/j.apenergy.2019.113694 (DOI)2-s2.0-85071887585 (Scopus ID)
Available from: 2019-10-01 Created: 2019-10-01 Last updated: 2020-04-20Bibliographically approved
Liu, C., Tapani, A., Kristoffersson, I., Rydergren, C. & Jonsson, D. (2019). En transportmodell med fokus på cykeltrafik: modellutveckling och scenarioanalyser. Linköping: Statens väg- och transportforskningsinstitut
Open this publication in new window or tab >>En transportmodell med fokus på cykeltrafik: modellutveckling och scenarioanalyser
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2019 (Swedish)Report (Other academic)
Alternative title[en]
A transport model with focus on bicycle trips : model development and scenario analysis
Abstract [sv]

Ökad andel resor med hållbara färdmedel är en förutsättning för att kombinera fortsatt tillväxt med minskad resursförbrukning och miljöpåverkan. I många europeiska städer har cykel blivit ett alltmer populärt färdmedel under de senaste decennierna. Dagens storskaliga transportmodeller, som utgör viktiga verktyg för utvärderingar och samhällsekonomiska analyser, är dock oftast fokuserade på modellering av resor med bil eller kollektivtrafik. Den här rapporten presenterar en tur-baserad transportmodell med syfte att bättre modellera cykelresor. Nyheterna i denna modell är bland annat ett detaljerat cykelnät som innehåller mer än 200 000 länkar och att modellen nyttjar en mer detaljerad zonindelning. Jämfört med nuvarande verktyget för samhällsekonomisk analys av cykelåtgärder, GCkalk, beskriver modellen ett fullständigt utbud och efterfrågan för cykel på detaljerad geografisk nivå. Modellen har skattats på data från den senaste resvaneundersökningen i Stockholms län från 2015 och representerar därmed observerat resebeteende. Modellen beaktar även cykel som anslutningsfärdmedel till resor med kollektivtrafik. Därigenom behandlar modellen cykel- och kollektivtrafik både som konkurrerande och som komplementära färdmedel och modellen kan utvärdera effekten av en förbättring av cykelinfrastrukturen på både enbart cykelresande och på cykel som anslutningsfärdmedel till kollektivtrafikstationer. Modellen är validerad mot cykelräkningar i Stockholm stad från september och oktober 2015. Modellen har testats på sex scenarier valda från Stockholms stads investeringsplan. Resultaten visar att investeringarna har en begränsad effekt på överflyttning mellan färdmedel och en måttlig effekt på befintliga cyklisters ruttval, restid och generaliserad kostnad.

Abstract [en]

Encouraging the use of active travel modes such as walking and cycling is vital for ensuring a sustainable urban development. In many European metropolitan areas, cycling is becoming increasingly popular within the recent decades. On the other hand, large-scale transport models, which serve as the main tools for policy evaluation and cost-benefit analysis, are often designed for modelling motorised travel modes such as private car and public transport. This study presents a tourbased transport model to better model cycling demand and supply. First, it uses a detailed bicycle network containing more than 200,000 links, covering the whole Greater Stockholm Area. Second, the model utilizes a refined zoning system with totally 5 808 zones each of the size of 250 m×250 m covering the entire Greater Stockholm Area. Third, the model is estimated on the newest Stockholm travel survey 2015, and therefore the model can represent travel behaviour that is up-to-date. In addition to the improvements mentioned above, the model also considers cycling as an access travel mode to a trip by public transport. Therefore, the model treats cycling and public transport as both competing and complementary modes, and the model is capable of evaluating the impact of an improvement in bicycle infrastructure on cycling, as well as on cycling to public transport stations. The model is then validated against bicycle count data from the City of Stockholm. Six scenarios are tested according to the investment plan from the City of Stockholm. The results show that the investments have a limited effect on modal shift but a moderate effect on the existing cyclists' route choice, travel time and generalised cost.

Place, publisher, year, edition, pages
Linköping: Statens väg- och transportforskningsinstitut, 2019. p. 144
Series
VTI rapport, ISSN 0347-6030 ; 1007
Keywords
Bicycle, Cycling, Journey, Forecast, Model (not math), Calculation
National Category
Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 113 Road: Cycling, walking and moped transport
Identifiers
urn:nbn:se:vti:diva-13706 (URN)
Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2020-01-17Bibliographically approved
Zhang, C., Campana, P. E., Liu, C., Wang, K., Zhang, Y. & Yan, J. (2019). Purchase Intention for Crowd-funded Milk Products with Integrated Photovoltaic Water Pumping Systems in China. In: Energy Procedia: . Paper presented at 2018 Renewable Energy Integration with Mini/Microgrid, REM 2018, 28 September 2018 through 30 September 2018 (pp. 503-508). Elsevier Ltd
Open this publication in new window or tab >>Purchase Intention for Crowd-funded Milk Products with Integrated Photovoltaic Water Pumping Systems in China
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2019 (English)In: Energy Procedia, Elsevier Ltd , 2019, p. 503-508Conference paper, Published paper (Refereed)
Abstract [en]

In comparison with current financing mechanisms for renewable energy systems, crowd-funding financing mechanism offers a new potential source of financing with recent use of social media. Crowd-funding financing mechanism can also increases the social supports for renewable energy systems as users and investors turn to be more actively engaged in energy systems. As a new potential source of financing, crowd-funding mechanism has different forms, including donation, lending, equity and product reward approaches. In this paper, discrete choice model was used to explore whether crowd-funding financing with a novel sociotechnical product reward practice, has the attractions for potential customers to pay for a more sustainable milk product with distributed photovoltaic (PV) system. We empirically investigated the reward-base crowd funding with the specific integrated photovoltaic water pumping (PVWP) system in dairy milk production in China. 48 in-depth interviews were adopted for qualitative analysis of determinants of customer milk purchase decision. The ordered probit regression was employed with 357 online surveys to systematically estimate the purchase intention for the online-crowd-funding sustainable milk. Customer behaviours, environmental consciousness, and the individual socio-demographic factors were tested as potential explanatory variables. In the survey and depth interview samples, we found interviewees as potential customers showed strong purchase intentions to the crowd funding dairy milk for noticing milk quality and nutritious improvement, emission reduction and environmental benefits by the integrated PVWP system. In our findings of the regression results, the females, customers with young children or planning to have children were found with higher willing to purchase than other customers for crowd funding the sustainable dairy milk. The familiarity and popularity with online shopping and pre-sale purchase in China made customers more open and active towards pre-pay and crowd-funding mechanism.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Financing, Alternative, Interview
National Category
Energy Systems
Research subject
SAB, Qb Managerial economics
Identifiers
urn:nbn:se:vti:diva-13731 (URN)10.1016/j.egypro.2018.12.008 (DOI)2-s2.0-85063770378 (Scopus ID)
Conference
2018 Renewable Energy Integration with Mini/Microgrid, REM 2018, 28 September 2018 through 30 September 2018
Available from: 2019-05-02 Created: 2019-05-02 Last updated: 2019-12-12Bibliographically approved
Böcker, L., Priya Uteng, T., Liu, C. & Dijst, M. (2019). Weather and daily mobility in international perspective: A cross-comparison of Dutch, Norwegian and Swedish city regions. Transportation Research Part D: Transport and Environment
Open this publication in new window or tab >>Weather and daily mobility in international perspective: A cross-comparison of Dutch, Norwegian and Swedish city regions
2019 (English)In: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340Article in journal (Refereed) In press
Abstract [en]

With climate change, weather has emerged as an important theme in transport research and planning. Although recent studies demonstrate profound weather effects on mobility in single case study areas, international cross-comparisons are required to reveal how effects differ between cities with different transport and climate regimes. This paper provides an international cross-comparison of the simultaneous effects of weather on destination choices, distances, trip chaining, and transport modes in the urban regions of Utrecht (Netherlands), Oslo and Stavanger (Norway), and Stockholm (Sweden). Hereto, regional subsamples of national travel survey data were linked to meteorological records for the three respective countries and analysed in generalised Structural Equation Models. Our findings generally indicate that light, calm, dry and warm atmospheric conditions may positively affect cycling and the selection of outdoor leisure destinations, while cold and to a lesser extent wet and windy weather conditions reduce cycling and enhance car use and travel optimising strategies like trip chaining, to reduce weather exposures. A positive effect of air temperature on cycling flattens out above 20–25 °C in most of our study areas, but hot weather does not seem to reduce cycling strongly. However, our findings also show considerable regional differences in the effects of weather on mobility. Both general effects and differences are interpreted in relation to geographical context, transport and land use, climate conditions, cultures, habits and adaptations and are discussed to formulate policies to mitigate active transport mode users’ exposures to adverse weather and make walking and cycling (even more) year-round modes.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Weather, Impact study, Journey purpose, Transport mode, Journey time, Urban area, Travel survey, Mathematical model
National Category
Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 11 Road: Personal transport
Identifiers
urn:nbn:se:vti:diva-14090 (URN)10.1016/j.trd.2019.07.012 (DOI)2-s2.0-85069632289 (Scopus ID)
Available from: 2019-08-19 Created: 2019-08-19 Last updated: 2020-04-20Bibliographically approved
Abenoza, R. F., Liu, C., Cats, O. & Susilo, Y. O. (2019). What is the role of weather, built-environment and accessibility geographical characteristics in influencing travelers’ experience?. Transportation Research Part A: Policy and Practice, 122, 34-50
Open this publication in new window or tab >>What is the role of weather, built-environment and accessibility geographical characteristics in influencing travelers’ experience?
2019 (English)In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 122, p. 34-50Article in journal (Refereed) Published
Abstract [en]

We examine the effect of weather, accessibility and built-environment characteristics on overall travel experience as well as the experience with the latest trips. These are factors that are often disregarded in the travel satisfaction literature even though they are believed to largely influence the first mile of the door-to-door trip. This study fills a research gap in investigating all these factors by using, amongst other, a relatively large travel satisfaction survey from years 2009 to 2015 and by focusing on urban and peri-urban geographical contexts, the city and county of Stockholm (Sweden), respectively. The ordered logit model results show that county dwellers living close to a metro station and in well linked-to-all areas report higher overall travel satisfaction evaluations. In addition, precipitation and ground covered with snow have a negative influence on travel satisfaction. Our findings indicate that built-environment characteristics exert a rather weak influence on the travel experience, especially in the peri-urban context. However, some aspects such as living in areas with medium densities, low income and with high safety perceptions around public transport stations are associated with higher satisfaction levels. In turn, areas with single land uses are found to have lower travel satisfactions. These results are important for public transport planners and designers in devising measures to prevent and mitigate the negative outcome of some weather conditions and to conceive better designed transit oriented developments.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Experience (human), Weather, Accessibility, Building (structure), Travel, Public transport
National Category
Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 11 Road: Personal transport
Identifiers
urn:nbn:se:vti:diva-13646 (URN)10.1016/j.tra.2019.01.026 (DOI)000465061400003 ()2-s2.0-85061906067 (Scopus ID)
Available from: 2019-05-17 Created: 2019-05-17 Last updated: 2019-12-12Bibliographically approved
Susilo, Y. O. & Liu, C. (2019). Who has more say on your daily time use?: A quantitative intra-household time-use altruism analysis. In: Goulias, K.G., Davis, A.W. (Ed.), Mapping the Travel Behavior Genome: (pp. 455-477). Elsevier
Open this publication in new window or tab >>Who has more say on your daily time use?: A quantitative intra-household time-use altruism analysis
2019 (English)In: Mapping the Travel Behavior Genome / [ed] Goulias, K.G., Davis, A.W., Elsevier , 2019, p. 455-477Chapter in book (Other academic)
Abstract [en]

This chapter focuses on the six typical shared activities, i.e. grocery shopping, household chores, babysitting, picking up children, relaxing, and social activities, and investigates on how a husband/wife’s time allocation on such activities is influenced by his/her spouse’s participation on the same activities and vice versa. The results show that the altruism behaviors differ substantially across different activity types. Income and the presence of children polarize husband’s altruism behaviors, and wives have a lot of power in influencing husbands’ time use allocations for activities such as baby-sitting. At the same time, the results also show the significant role of opportunities, such as accessibilities to wider crowd and amenities, in shaping household members’ altruism behaviors.

Place, publisher, year, edition, pages
Elsevier, 2019
National Category
Human Geography
Identifiers
urn:nbn:se:vti:diva-15232 (URN)10.1016/B978-0-12-817340-4.00023-1 (DOI)2-s2.0-85082028080 (Scopus ID)9780128173404 (ISBN)
Available from: 2020-05-08 Created: 2020-05-08 Last updated: 2020-05-08Bibliographically approved
Liu, C., Susilo, Y. O. & Dharmowijoyo, D. B. E. (2018). Investigating intra-household interactions between individuals’ time and space constraints. Journal of Transport Geography, 73, 108-119
Open this publication in new window or tab >>Investigating intra-household interactions between individuals’ time and space constraints
2018 (English)In: Journal of Transport Geography, ISSN 0966-6923, E-ISSN 1873-1236, Vol. 73, p. 108-119Article in journal (Refereed) Published
Abstract [en]

The activity space of an individual is defined as the activity-travel environment which a traveller is using for his or her activities. It is limited by this individual's ability and resources, such as available time for travel as well as his or her anchor points. However, most existing studies have focused on single individual activity space, ignoring the fact that individuals’ activities often interact with that of his or her family members’. In this paper a multivariate model is proposed where the correlation between travel time of fathers and mothers, and the correlation between the activity space and travel time are modelled explicitly. The estimated correlations from these joint distributions provide insights into both the intra-household interactions in daily travel and the intrinsic relationships of the hidden limits in the dimensions of space and time. The travel time limits are modelled using a stochastic frontier model component, which can estimate an unobserved upper or lower limit for travel time expenditure. This limit usually refers to the maximum travel time budget or minimum travel time need, which denotes the maximum or minimum amount of travel time that an individual is willing or able to allocate per day. The concept of the confidence ellipse is used as a measure of activity space constructed from the multi-day travel diary data. It is hypothesised that the unobserved travel time limits and activity space sizes of fathers and mothers are correlated with each other, due to a similar spatial knowledge and accessibility to various facilities. The daily variations in the travel time expenditure of parents are also assumed to be correlated because of daily household task allocation and joint household travel. Data collected from a three-week household travel diary in the Bandung Metropolitan Area in Indonesia are used for estimation in this study. The estimated frontier model component shows that neither parent has reached their maximum travel time budget and/or minimum travel time need that they inherently must spend. Compared with other attributes, the perceived accessibility attributes play the most important role in influencing the activity space limits. For households with fully employed fathers, a trade-off mechanism is found in travel time expenditure between parents, which is likely due to the redistribution of household tasks. On the other hand, for households with fathers who are not fully employed, a complementary effect is found, arising from the joint travel among household members. The travel time budget and activity space limits of fathers are positively correlated with those of mothers. These findings call for the formulation of transport policies that consider the household as a unit, especially in developing countries such as Indonesia, to fulfil the mobility needs of different market segments, e.g., households with fully employed fathers and those with fathers who are not fully employed.

Place, publisher, year, edition, pages
Elsevier Ltd, 2018
Keywords
Household, Travel, Journey time, Mathematical model, Estimation, Accessibility
National Category
Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 11 Road: Personal transport
Identifiers
urn:nbn:se:vti:diva-13368 (URN)10.1016/j.jtrangeo.2018.10.015 (DOI)000451938900010 ()2-s2.0-85055664822 (Scopus ID)
Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-12-12Bibliographically approved
Susilo, Y. O., Liu, C. & Börjesson, M. (2018). The changes of activity-travel participation across gender, life-cycle, and generations in Sweden over 30 years. Transportation, 1-26
Open this publication in new window or tab >>The changes of activity-travel participation across gender, life-cycle, and generations in Sweden over 30 years
2018 (English)In: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, p. 1-26Article in journal (Refereed) Published
Abstract [en]

This study utilised the Swedish national travel survey covering a period of over 30 years. We investigated the long-term trends in activity-travel patterns of individuals in different life-cycle stages and generations using cohort analysis and a path model. The main findings are summarised as follows. The women, including mothers, in younger generations have become more active in out-of-home non-work activities and their trip chaining has become more complex, compared to their male counterparts. While men are still driving more than women, the gap is decreasing in the younger generations. The gender difference among teenagers in terms of out-of-home time use diminishes in younger generations. Teenagers of younger generations spend more of their leisure time inside their homes, possibly due to the rise of online activities and gaming and more time-consuming school trips, the latter attributed to changes in school choice policy. Older adults travel more, possibly due to better paratransit transport service, supported by better health services.

Place, publisher, year, edition, pages
Springer New York LLC, 2018
Keywords
Travel survey, Long term, Behaviour, Man, Woman, Adolescent, Old people
National Category
Public Health, Global Health, Social Medicine and Epidemiology Transport Systems and Logistics
Research subject
10 Road: Transport, society, policy and planning, 11 Road: Personal transport
Identifiers
urn:nbn:se:vti:diva-12862 (URN)10.1007/s11116-018-9868-5 (DOI)2-s2.0-85044018623 (Scopus ID)
Available from: 2018-04-05 Created: 2018-04-05 Last updated: 2020-01-16Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6966-9077

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