Archipelagos are rural regions characterized by their distinct geo-graphic layouts with many separated island communities. Water bodies hinder access to community services and make a well-functioning ferry-based public transport system the only feasible means of mass transportation. Both between islands and to connect to the mainland. Maritime environments provide great routing flexibility. However, outdated or imprecise nautical charts can hinder the safe use of such possibilities in commercial traffic. 

This thesis develops methods for strategic planning of archipelago transportation systems, enabling the valuation of novel fairways. Contributions are made to the fields of applied optimization and statistical modeling of spatial data considering the distinct features of archipelago environments. 

To improve the inference of fairways, a data fusion model for combining traditional bathymetric data and ship trajectory data from the automatic identification system (AIS) for depth inference is developed. It utilizes probabilistic modeling and survival analysis for spatial interpolation of the two qualitatively different sources of information. To handle the large amounts of automatic identification system (AIS) data and the non-stationarity cause by holes (islands) in the model region, a discretized mesh approach is used. 

In the second step an optimization model for joint network design and scheduling of ferry public transport, with the capability of evaluating currently unavailable fairways with opening costs. In this study, characteristic features of archipelago ferry networks are identified. These features are then expressed using a modified vehicle routing model with multiple trips. Results show that factors such as traffic requirements, operating costs and fleet composition has a large impact on the value of a fairway. 

In summary, the thesis develops methods for inferring novel fairways using the alternate source of information provided by ship trajectory data. To evaluate such fairways, an optimization model for assessing their scheduling value in ferry based public transport systems is developed. 

Society today is permeated in many respects by digitalization – a continuous process that generates and is expected to generate benefits for both the individual and society. The transport sector is no exception. Digitalization with data as a foundation forms the basis for vehicles and service concepts such as autonomous vehicles, MaaS, smart mobility, electrification and intelligent infrastructure. These technologies and services are associated with and offer hopes for reduced environmental and climate impact, fewer delays, more choices for the individual, increased accessibility, more efficient use of vehicles and infrastructure and improved traffic safety.

Children in different age groups have been identified in previous research as a group that is not always considered in the planning and design of the transport system. But regardless of age, socioeconomic background and geography, children are part of the transport system every day, whether it is walking and cycling on their own or with friends, to and from school, or to leisure activities in their parents' car, together with others on public transport or together with others through contact via mobile phone. The digitalization of the transport system that is currently underway affects and will affect children and shape their everyday mobility.

The purpose of the following literature review is therefore to highlight the ways in which current research highlights the opportunities and obstacles that a digitalized transport system has and is expected to have on children's mobility and accessibility. The guiding questions are:

• What risks, concerns and hopes are there for children and their parents in a more digitalized transport system?
• What attitudes do children themselves have towards a digitalized transport system?
• What attitudes do parents and other adults have towards a digitalized transport system?

This article presents the results of a systematic literature review on the use of Intelligent Learning Systems (ILS) in simulator-based professional education contexts aiming to provide guidelines on how to design a personalized, flexible, and adaptive learning experience to be used in remote simulator training for maritime cadets. The PRISMA protocol was employed to identify empirical studies published in international academic journals between 2018–2023. In the first step, 782 records were identified through searching through Scopus and Web of Science. After screening abstracts and full texts, a total of 10 studies remained. The article synthesizes results from three different domains where ILS have been used for simulator-based professional training: social science education, healthcare, and transportation. The results show a wide variety of applications and approaches to ILS design, such as to enhancing motivation and satisfaction in the students’ learning process through adaptive feedback, or to provide real-time evaluations and feedback to trainees. The review shows the importance of considering end-user groups and how these may make use of the system in the design of an ILS. While systems can offer modules to both instructor and trainee, it is important to recognize that the two are different in terms of what is needed to facilitate an effective, efficient, and learner-centered training path.

A sufficiently smooth and comfortable cycle path is necessary for increased and safe cycling. The current requirements for state cycle paths are the same as for car roads and are based on the comfort experience when driving a car, which does not correspond to the experience when cycling. Therefore, the requirements for cycle paths need to be changed to be more appropriate. 

In this research project funded by the Swedish Transport Administration, VTI, in collaboration with Ramboll RST, has developed a proposal for a new evenness indicator and a measuring method adapted for cycle paths that can be used in contract performance control of newly laid surfaces. The proposal is based on literature reviews, longitudinal profile measurements and cyclist assessments, as well as testsin practice in pavement condition assessments of cycle paths commissioned by Region Skåne and the City of Malmö. The proposed evenness indicator is based on a longitudinal profile measured with laser profiler where the root mean square (RMS) is calculated over a step length of 25 mm and where wavelengths over three meters are filtered out. We have chosen to call the evenness indicator BCrms3 (BiCycle-rms, maximum wavelengths of 3 meters). The indicator thus describes the evenness of cycle paths with wavelengths ranging from 0.05 to 3 meters, relating to what is the most important for cyclists' riding comfort through the vibrations and shocks they cause. The limit value for BCrms3 is proposed to be initially 1.0 but can be adjusted according to purpose and needs. Since there is a risk that irregularities in the shorter unevenness range, i.e. imperfections in the texture, are not fully captured by the indicator, we propose that it be supplemented with a requirement for MPD (Mean Profile Depth) in connection with contract performance control. MPD is a standardized measure for macrotexture. Considering cyclists' comfort and safety (friction), an approved pavement should have a requirement for an MPD between 0.45 and 1.3 mm. Both indicators could also be used for maintenance management, but with other suitable limit values. 

Tyre wear is one of the largest sources of microplastic emissions both in Sweden and globally. Being able to estimate the size of this emission and how it changes in relation to changes in regulations, the vehicle fleet and tyre development is important for assessing the impact on ecosystems and health. The purpose of developing an indicator for tyre wear is to be able to update and monitor changes in national emissions and how different vehicle categories affect these in a manageable framework. The methodology for the indicator was originally developed within a government commission, where emission factors for tyre wear in passenger cars and light trucks were measured by weighing discarded tyres. For heavy traffic, there are no national measurements of emission factors, which is why current detailed data from the Netherlands has been rescaled for Swedish vehicles through weight and tyre number differences. Weight differences have also been used to scale emission factors between passenger cars, light lorries and motorcycles. The emission factors have then been combined with detailed data on annual milage and finally summarised. To make the indicator manageable, a calculation tool has been developed with instructions on what can be updated and at what intervals. 

This report provides a knowledge base for assessing the applicability of exemptions under Article 17 of the EU Ambient Air Quality Directive (2024/2881), which allows exceedances of PM₁₀ limit values to be exempt from action plans if they can be attributed to winter road sanding or salting. The aim is to compile current knowledge on how winter road maintenance affects PM₁₀ levels and to analyze methodologies for quantifying these contributions. 

The findings show that both sand and salt contribute to PM₁₀, but sanding generally has a greater impact, particularly through the resuspension of road dust in spring. At the same time, it is very difficult to distinguish the contribution from sand from other sources, such as wear from studded tyres, making it problematic to meet the directive’s requirement for unambiguous source identification. Salt is considered to have less adverse health effects and is easier to identify in air samples. It can also be used as a substitute for sand to reduce PM₁₀ emissions.  

The study concludes that the directive lacks a clear justification for the exemption, and that the exemption risks undermining efforts to improve air quality. There is no new knowledge supporting that the sources should be excluded based on health effects and being anthropogenic, their contribution to PM₁₀ can be mitigated. Several Member States have applied the exemption, often without being able to demonstrate clear source attribution, especially for sand. In the Swedish context, the combined use of sanding and studded tyres makes the exemption particularly difficult to apply.  

The report recommends that Sweden should not apply Article 17 in its current form, but that a limited exemption for road salt could be considered. Furthermore, it is proposed that the European Commission should clarify which specific measures related to winter sanding and salting must be taken before the exemption can be used, and that future research should focus on developing methods to distinguish sources of PM₁₀. 

This paper presents a new conceptual framework, and stepwise approach to populate it, for informing countermeasure development to support fitness-to-drive for professional drivers. Professional drivers are vital to the transport network; however, the job is demanding and drivers are vulnerable to impairments which may impact safe driving. Countermeasures are any action or activity that mitigates the impact or frequency of occurrence of driver impairment. The framework proposes countermeasures to be delivered across three time points: Operational (during shift), Tactical (immediately after shift) and Strategic (outside of on-shift) and at multiple system levels, e.g., driver, manager, enforcement etc. The framework was successfully pilot tested with three different professional driver use cases: autonomous shuttles, taxi, and garbage truck drivers. This structured approach to countermeasure design offers potential to improve driver health and enhance road safety. The work was conducted within , an EU project, grant agreement number .

In the project SHIPNOISE we have developed a measurement station for both airborne and underwater noise from ships underway. The airborne noise levels indicate that there is a risk to exceed recommended indoor low-frequency noiselimits for dwellings positioned up to several hundred meters from the passing ships, although the effect on public health is uncertain.

The underwater noise recorded at the SHIPNOISE measurement locations is strong enough to have an environmental impact on harbour porpoises, fish and also to some extent on invertebrates. During ship passages, thresholds for several different effects are exceeded. Harbour porpoises, herring and salmon are likely to avoid or escape the area when a loud ship passes. These effects are far more common at Böttö than at Lurö. Cod reproduction is also likely to be affected, again more at Böttö than at Lurö. The noisiest ships may even cause temporary hearing damage to porpoises at Böttö. 

The original purpose of this project was to construct a test section of a double-layer porous asphalt pavement where steel slag was used as the aggregate in the wearing course. The contents of the project also included a summary of the performance of earlier tests with steel slag as the aggregate in dense pavements in Sweden. It was also found that including an international literature review would be very useful. The literature review was not comprehensive but included the latest and most relevant findings. Among many advantages for steel slag over natural aggregates, the literature mentions durability, less rutting and dark colour. Also polished stone values and abrasion resistance are generally high. The main disadvantage is the higher mass which makes transportation from steel works to paving sites more expensive. Some of the dense Swedish steel slag pavements presented in this report have served well for long times, under moderate or high traffic volumes. The overall assessment comes out quite positive. The main subject in this report, is a test of steel slag aggregate in the top layer of a double-layer porous asphalt pavement paved in 2017 on motorway E4 in Huskvarna, in this report followed until 2023. This project started, as planned, in 2016 with laboratory studies aiming at gaining experience of designing steel slag pavements with high air voids content for durable performance, especially with traffic noise reduction in focus. This trial section was paved simultaneously when the double-layer pavement through Huskvarna had to be repaved where then the main section could serve as a control or reference section. Both the test and the control sections had an identical bottom layer while the top layer of the test section had the stone aggregate replaced by steel slag. In this way it has been possible to compare the performance of the steel slag section with a longer section of double-layer porous asphalt which is using only natural coarse aggregates.

Dummy responses in a crash test can vary depending not only on the change of velocity but also on how the impact was generated. Literature reporting how acceleration pulses can vary in cars impacted in different configurations is limited. The aim of this study was to collect and categorise different acceleration pulses in 3 different types of rear collision. The acceleration pulse resulting from a solid, 1000 kg, mobile barrier test at 40% overlap and an impact velocity of 15 km/h was studied for 33 different cars. Seven cars were impacted at 100% overlap at higher impact velocities using the same mobile barrier. Acceleration pulses from two different car types in real-world collisions producing a similar change of velocity were also analysed.

The results from the barrier tests show that a similar change of velocity can be generated by a large variety of pulse shapes in low velocity rear impacts. The results from real-world collisions showed that a similar change of velocity was generated in different ways both in terms of peak and mean acceleration. The results of this study highlight the importance of knowing the acceleration pulse both when evaluating the severity of a real world crash and when designing test methods for evaluating vehicle safety performance in low velocity rear-end impacts, particularly in respect of soft tissue neck injuries. 

The aim of the study was to validate the BioRID P3, an improvement of the BioRID I, in regular car seats against rear-end impact volunteer test data and compared it to PMHS data collected previously. The performance of the BioRID P3 was also compared to the performance of a Hybrid III equipped with a TRID neck. The volunteer tests were performed at a change of velocity (Δv) of 10 km/h and a maximum acceleration of 3.5 g. The PMHS (Post Mortem Human Subject) tests were run at Δv of 10 and 15 km/h. The BioRID P3 acceleration and displacement data correlated well with the volunteer and PMHS data. Comparison of the head and chest horizontal displacement and the horizontal neck forces data showed differences between the dummies. 

Around 10 percent of Swedish students have neurodevelopmental disorders (NDD), such as ADHD and ASD and the numbers have been increasing. Individuals with NDD tend to face more challenges in driving and driver training compared to others. Swedish authorities are currently reviewing the driver education system to increase drivers’ awareness of risks and environmental considerations. To ensure that the new curriculum better accommodates the needs of individuals with NDD, this study aims to explore the challenges faced by autistic individuals and individuals with ADHD during the driver's license process, as well as their willingness to share these challenges with educators and driving examiners. A questionnaire study was conducted among individuals either in the process of obtaining their driver's license or who had recently obtained it. Out of 217 respondents, 34 had ADHD, 14 had ASD, and 24 had both ADHD and ASD. This study offers novel insights into the challenges during the driving license process for individuals with NDD. Results show that individuals with ADHD and ASD seeking a driver's license encounter challenges throughout the process, especially those with ADHD or a combination of ADHD and ASD. Respondents in the diagnosis groups are more willing to share their challenges, suggesting their awareness of the benefits. Still, there is an important discrepancy between wanting to share and knowing when to. Since driving simulators can create specific training scenarios and have proven effective in improving driving performance, practicing reported challenges such as positioning, task switching, and rule adherence in a driving simulator could help reduce challenges for driver students with NDD. Individual variations make effective communication crucial to reducing challenges in the driver's license process for individuals with NDD. Therefore, alternative communication methods, such as for example simplified language, should be further explored, alongside the implementation of a mandatory information sheet addressing individual challenges for all learner's permit applicants.

Background

Mild traumatic brain injuries (mTBI), including concussions, following traffic accidents is common. How often these injuries lead to sickness absence (SA) among working aged individuals is however insufficiently studied. Thus, the aim of this study was to examine frequency of new SA following mTBI sustained in a road traffic environment and its associations with sociodemographic and injury-related factors.

Method

Nationwide population-based register study. Working aged individuals (18–63), living in Sweden, who in 2014 to 2016 acquired an mTBI in a traffic accident were included based on in- and specialised out-patient health care records. Information on SA (> 14 days), disability pension, pre-injury factors (age, sex, education, marital status, type of living area, country of birth, income from work) as well as injury-related factors (type of road user, in- or outpatient health care) were used in analyses of risk factors for a new SA-spell. Odds ratios (ORs), both crude and adjusted, with 95% confidence intervals (CIs) were estimated with logistic regression.

Results

6073 individuals were identified. 12% had a new SA spell after injury. Sociodemographic risk factors were female sex, older age and being born outside Sweden. Car occupants had higher ORs for new SA, compared to pedestrians, bicyclists, and other road users, and was also associated with longer duration spells (> 90 days). Having received in-patient health care was associated with an OR of 3.7 for new SA compared to those only receiving out-patient health care (including emergency department visits). Having received in-patient health care was also associated with longer duration spells.

Conclusion

A traffic related mTBI is most often a benign injury, seldom resulting in a new SA spell of longer duration. When it does, it is more likely to involve car occupants, and those who have required in-patient health care. 

A shift in modal share from car driving to cycling has many benefits, e.g., health benefits from increased physical activity and less pollution and congestion. A smooth cycle path surface with sufficient friction is important for cyclist traffic safety, comfort and level of service. Cracks and surface unevenness are frequent maintenance-related deficiencies associated with the degradation of the structure. A purpose of this thesis is to identify degradation factors specific for cycle paths, through a state-of-the-art literature review. The review is complemented by four appended papers. Paper A analyses the stated distress modes and causes reported on Swedish municipal cycle paths with respect to climatic and population data. Paper B evaluates a novel method for condition assessments on cycle paths related to cycling comfort—the Bicycle Measurement Trailer. PaperC proposes alternative deflection bowl parameters for structural evaluation of cycle paths from in-situ falling weight deflectometer and light weight deflectometer measurements. Paper D reports on the results of full-scale testing on instrumented cycle path structures. The main results from the papers indicate that surface roughness and unevenness, longitudinal cracks and edge deformations are the most common distress modes. The main reasons behind this distress are structural interventions, tree roots, frost heave and heavy vehicles. The load-bearing capacity close to the pavement edge and at increased moisture content is reduced. The proposed alternative approaches for cycle path condition assessment were able to assess the surface roughness and evenness, along with the structural condition, for practical applications on the investigated cycle paths. The conclusions of the thesis suggest that the structural design principles for cycle paths in the Swedish structural design manual needs to be updated. Models that better describe the behaviour of thin-surfaced asphalt pavements, especially with respect to climate, should be developed. More studies are recommended to validate the proposed condition assessment approaches.

Background

Vision is a critical component of safe driving, yet establishing effective legal vision requirements for driver licensing remains challenging. Current EU regulations mandate minimum standards for visual acuity and visual fields, but also allow exemptions based on practical driving tests. This study investigates the on-road driving performance of individuals with visual field loss (VFL) who regained their licences after passing a simulator-based assessment, compared to age-matched and younger, normally sighted controls.

Method

The study included 72 individuals with VFL who had successfully completed a simulator test and regained their driver's licences. Each participant was matched with an age- and gender-matched normally sighted control and a younger normally sighted control (in total 212 participants). All participants underwent a standardized on-road driving test administered by certified examiners blinded to group allocation. The test evaluated vehicle knowledge, eco-driving, adherence to traffic rules and traffic safety/behaviour using the Swedish national driving test protocol. Logistic regression analysis was performed to assess factors influencing pass rates.

Results

Participants with VFL achieved a pass rate of 68%, comparable to the age-matched controls (66%) but lower than the younger controls (81%). No significant differences were observed in the proportions of passed tests, test elements, driving habits or interventions across groups. Within the VFL group, neither diagnosis type (e.g., glaucoma, stroke) nor the extent of visual field loss predicted test outcomes. While older groups (VFL and age-matched controls) received more remarks regarding observational competence compared to younger controls, no differences emerged in risk identification or other competence areas.

Conclusions

This study suggests that individuals with VFL can drive as safely as age-matched, normally sighted controls. Simulator and on-road tests are critical tools for individualized assessment, challenging the sole reliance on perimetry for licensing decisions. These findings support the inclusion of practical on-road driving tests as a regulatory option for individuals with VFL, promoting mobility while maintaining road safety.

The carbon footprint of bio-extended bituminous binders aiming for pavement decarbonisation was quantified using a “cradle-to-pavement” life cycle assessment. The binders were extended with a plant-based bio-oil. By biogenic carbon accounting, the impact of biogenic carbon flow was analysed through different approaches. The results indicated that using the bio-oil as a bitumen extender slightly increases the fossil global warming potential (GWP) of asphalt pavements, by about 1%. Both the absolute GWP levels and the effect of polymer modification on average annual GWP are variable, depending on the input data. When the “−1/+1” approach is adopted, two of the three analysed cases showed a lower average annual GWP of asphalt pavements with polymer-modified bitumen while one analysed case showed almost unchanged average annual GWP. All analysed cases confirmed that the biogenic carbon accounting by the “−1/+X” approach reduces the total and average annual GWP significantly for the cases with biogenic components.