| 1. |
- Andersson, Jan, 1965-, et al.
(author)
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Bygdeväg : När 2 filer blir 1
- 2023
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Reports (other academic/artistic)abstract
- Sundbyberg kommun har genomfört en ombyggnation av en del av Ursviksvägen. En traditionell tvåfilig väg med skyltad hastighet på 30 km/tim byggdes om till en fil för bilar och två cykelfält, en på vardera sida om körfältet för bilar, det vill säga en 2 minus 1-väg. Före ombyggnation och efter ombyggnation tillfrågades boende och passerande individer om deras upplevelser av Ursviksvägen. I synnerhet var det utifrån perspektivet säkerhet och framkomlighet, vilket i sin tur kan kopplas till livskvalitet. Dessutom monterades kameror upp längs sträckan som registrerade trafikarbetet samtidigt som insamlandet av individers upplevelser pågick. Resultaten från enkäten är mycket entydiga. Ombyggnation av delsträckan på Ursviksvägen mottogs väldigt väl. Den upplevda tryggheten, säkerheten och framkomligheten påverkades positivt, i synnerhet för cyklister och fotgängare. Bussresenärers upplevelse var också positiv även om effekten av ombyggnationen inte var lika stark. Dessa resultat erhålls utan att bilisters upplevelse av framkomlighet försämrades. Ytterligare analyser visade att om man var nöjd med säkerheten, tryggheten och framkomligheten i området var man också mera nöjd med området runt Ursviksvägen.En rad analyser genomfördes efter detta huvudresultat för att försöka förstå variationen i svaren bättre. I huvudsak studerades om svaren på frågorna påverkades av om respondenten nyttjade Ursviksvägen som fotgängare, bilist, bussresenär eller cyklist. Dessutom analyserades om ombyggnationen lett till ett förändrat färdmedelsval. Slutligen analyserades om de respondenter som har barn i de skolor som ligger utmed Ursviksvägen har andra upplevelser än de respondenter som inte har barn vid en skola utmed Ursviksvägen. Oavsett hur data analyserades framkom positiva effekter av ombyggnationen. Ett exempel på analys där respondenter med barn i skolor utmed Ursviksvägen jämfördes med respondenter utan barn.Resultatet visade att respondenter med barn i någon av skolorna var signifikant nöjdare med alla de aspekter i trafikmiljö som enkäten berörde men detsamma gällde även de som inte hade några barn i skolorna. Däremot visade resultaten att respondenter med barn i skolorna var mindre nöjda med området innan ombyggnationen vilket innebar att de stod för den största ökningen. Värt att poängtera är också att eftermätningen visade att föräldrar som hade barn som gick eller cyklade till skola var måttligt nöjda med tryggheten och säkerheten för sina barn, då det högsta medelvärdet var drygt 4 på den 7-gradiga skalan.
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| 2. |
- Andersson, Jan, et al.
(author)
-
När 2 filer blir 1: Ombyggnation av Ursviksvägen i Sundbyberg
- 2023
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Reports (other academic/artistic)abstract
- Sundbyberg kommun har genomfört en ombyggnation av en del av Ursviksvägen. En traditionell tvåfilig väg med skyltad hastighet på 30 km/tim byggdes om till en fil för bilar och två cykelfält, en på vardera sida om körfältet för bilar, det vill säga en 2 minus 1-väg. Före ombyggnation och efter ombyggnation tillfrågades boende och passerande individer om deras upplevelser av Ursviksvägen. I synnerhet var det utifrån perspektivet säkerhet och framkomlighet, vilket i sin tur kan kopplas till livskvalitet. Dessutom monterades kameror upp längs sträckan som registrerade trafikarbetet samtidigt som insamlandet av individers upplevelser pågick. Resultaten från enkäten är mycket entydiga. Ombyggnation av delsträckan på Ursviksvägen mottogs väldigt väl. Den upplevda tryggheten, säkerheten och framkomligheten påverkades positivt, i synnerhet för cyklister och fotgängare. Bussresenärers upplevelse var också positiv även om effekten av ombyggnationen inte var lika stark. Dessa resultat erhålls utan att bilisters upplevelse av framkomlighet försämrades. Ytterligare analyser visade att om man var nöjd med säkerheten, tryggheten och framkomligheten i området var man också mera nöjd med området runt Ursviksvägen.En rad analyser genomfördes efter detta huvudresultat för att försöka förstå variationen i svaren bättre. I huvudsak studerades om svaren på frågorna påverkades av om respondenten nyttjade Ursviksvägen som fotgängare, bilist, bussresenär eller cyklist. Dessutom analyserades om ombyggnationen lett till ett förändrat färdmedelsval. Slutligen analyserades om de respondenter som har barn i de skolor som ligger utmed Ursviksvägen har andra upplevelser än de respondenter som inte har barn vid en skola utmed Ursviksvägen. Oavsett hur data analyserades framkom positiva effekter av ombyggnationen. Ett exempel på analys där respondenter med barn i skolor utmed Ursviksvägen jämfördes med respondenter utan barn.Resultatet visade att respondenter med barn i någon av skolorna var signifikant nöjdare med alla de aspekter i trafikmiljö som enkäten berörde men detsamma gällde även de som inte hade några barn i skolorna. Däremot visade resultaten att respondenter med barn i skolorna var mindre nöjda med området innan ombyggnationen vilket innebar att de stod för den största ökningen. Värt att poängtera är också att eftermätningen visade att föräldrar som hade barn som gick eller cyklade till skola var måttligt nöjda med tryggheten och säkerheten för sina barn, då det högsta medelvärdet var drygt 4 på den 7-gradiga skalan.
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| 3. |
- Andersson, Jan, 1965-, et al.
(author)
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Two minus one road equals improved quality of life
- 2024
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In: Transportation Research Interdisciplinary Perspectives. - : Elsevier. - 2590-1982. ; 26
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Journal article (peer-reviewed)abstract
- Background: Sundbyberg municipality (part of greater Stockholm) has reconstructed a traditional two-lane road, with an allowed speed limit of 30 km/h, into a road with one car lane and two bicycle lanes, one on either side of the car lane (a “two minus one road”). The aim was to increase traffic safety and accessibility, especially for bicyclists and pedestriansMethod: The design used was a before- an after-study including both subjective and objective measures. To collect subjective data a survey measuring quality of life was used by asking residents and travellers how they experienced the road and their neighbourhood. The collection of objective data was done with the help of video cameras recording traffic conflicts, vehicle speed and position on the roadResults: The reconstruction of the road had positive effects on quality of life in general, specifically safety, security, and accessibility for bicyclists and pedestrians. Something which was achieved without reducing car drivers’ experience of accessibility. Subsequent analyses were conducted to increase the understanding of different ‘sub-groups’. Specifically, analyses assessed: if responses could be linked to modal choice; whether the reconstruction of the road resulted in a modal shift; and whether it was any differences between respondents who had or had not a child attending any of the local schools. Overall, the responses from the ‘sub-groups’ were not significantly different from each other (except for respondents with children). The video analyses on traffic safety showed no differences in conflicts before and after the reconstruction. The only negative result was that car drivers’ speed increased by 3 km/hConclusion: The reconstruction of roads with a traffic intensity, equivalent to the selected road is suitable for a two minus one road. Traffic safety, security, and accessibility will increase, but not at the expense of car drivers’ accessibility.
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| 4. |
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| 5. |
- De Ceunynck, Tim, et al.
(author)
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Interact or counteract? Behavioural observation of interactions between vulnerable road users and autonomous shuttles in Oslo, Norway
- 2022
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In: Traffic Safety Research. - : Dept. of Technology & Society, Faculty of Engineering, LTH, Lund University. - 2004-3082. ; 2
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Journal article (peer-reviewed)abstract
- The current paper presents the results of behavioural observations in a field experiment with automated shuttles in Oslo, Norway. Video observations were conducted at five fixed locations along a challenging 1.2 km automated shuttle line with varying traffic conditions. Observed interactions between vulnerable road users and automated shuttles were coded using a predefined codebook, which allowed a structured quantitative analysis. The paper identified several potentially risky types of situations in which the automated shuttles did not always behave according to the traffic rules. Generally, the automated shuttles failed to give way to pedestrians at pedestrian crossings in 26%–50% of the interactions. Right-turning shuttles failed to yield to cyclists going straight in 38% of the interactions at observation Site 1 (the only location where the automated shuttle takes a right turn). In majority of same direction interactions between cyclists and automated shuttles, the interactions resulted in the cyclist overtaking the automated shuttle, usually on the left-hand side. Generally, the paper found little evidence of road users trying to bully or otherwise take advantage of the defensive driving style of the automated shuttles and identified only a limited number of interactions in which a vulnerable road user behaved ignorant or aggressive towards the automated shuttles. In addition, the paper found very little indication of temporal effects that suggest changes in the interaction patterns over time.
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| 6. |
- Hammad, Samir, et al.
(author)
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Utvärdering av hastighetssäkrade åtgärder på landsbygdsvägar
- 2023
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Reports (other academic/artistic)abstract
- Detta arbete har utvärderat hastighetssäkrade åtgärders effekt på landsbygdsvägar genom att filma totalt 34 olika sådana åtgärder i södra Sverige och studera hastigheten av frigående bilar och tunga fordon när de passerar de olika åtgärderna.Varje plats har filmats med drönare och alla fordon har automatiskt spårats m.h.a. videoanalys. Därefter har frigående fordon identifierats och deras hastighet analyserats.Analysen har gjorts i två huvudsakliga steg: (1) en visualisering av fordonens rörelser genom alla studerade åtgärder har gjorts och hastighetsprofilerna återfinns i Bilaga A, B och C; och (2) en matematisk modell har skapats som beskriver förhållandet mellan ett fordons minsta radie genom en åtgärd och fordonets hastighet i samma punkt.Resultaten visar att de studerade hastighetssäkrade åtgärderna på landsbygdsvägar fungerar generellt bra och sänker hastigheten. Alla platser fungerar dock inte lika bra och det är fortfarande oklart exakt vad som avgör varför vissa platser med liknande åtgärder fungerar olika bra. Generellt så verkar Avsmalningar vara mest hastighetssänkande, Portar resulterar i 16% högre hastighet och Chikaner visar 30% högre hastigheter än avsmalningar.
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| 7. |
- Johnsson, Carl, et al.
(author)
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A relative approach to the validation of surrogate measures of safety
- 2021
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In: Accident Analysis and Prevention. - : Elsevier BV. - 1879-2057 .- 0001-4575. ; 161
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Journal article (peer-reviewed)abstract
- Surrogate measures of safety (SMoS) are meant to be an alternative/complement to crash data that enables a proactive approach to traffic safety. Validity is a fundamental property of SMoS that describes how well they reflect the quality of interest – traffic safety. However, typical validation studies are extremely resource demanding. Therefore, the aim of this study was to explore a relative approach to validity that uses fewer resources and does not rely on crash records from the observed locations. The core idea of a relative approach tothe validation of SMoS is that while SMoS might not accurately estimate the expected number of crashes, they still work well for comparisons between different sites or between conditions at the same site. Based on thisconcept, we propose a method in which a ground truth based on literature can be used as a baseline that can then be compared to the safety analysis of an SMoS study. Using the proposed method, a case study of six intersectionsin northern Europe was conducted, focusing on bicycle infrastructure. The results indicate that the minimum time-to-collision indicator is in line with the ground truth, whereas the post-encroachment time indicator is not.
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| 8. |
- Johnsson, Carl, et al.
(author)
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Exploring Space Syntax Integration at Public Transport Hubs and Public Squares Using Drone Footage
- 2022
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In: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 13:13
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Journal article (peer-reviewed)abstract
- Space Syntax theory is a methodological framework for describing and analysing the relationships between spaces and buildings. The fundamental building blocks of Space Syntax are called axial lines, which represent lines of sight from a specific point in space. These lines can then be used to quantitatively analyse the integration (or attractiveness) of an area. However, many public squares and transport hubs are crossed by roads which prove a hinderance when walking although not impairing the sightlines of pedestrians. The aim of this paper is to test how this limitation affects the concept and whether Space Syntax is still useful to understand how people move in such areas. Seven public squares and transport hubs in Malmö (Sweden) were selected and their Space Syntax integration was calculated. These values were compared with pedestrian detections from the same areas based on video recordings from a drone. When aggregating the areas into several levels based on their integration value, the result shows a clear link between Space Syntax integration and the number of pedestrian detections made at each location, demonstrating how this measure could be useful for understanding micromobility usage on a small scale.
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| 9. |
- Johnsson, Carl, et al.
(author)
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Identification of evasive manoeuvres in traffic interactions and conflicts
- 2022
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In: Traffic Safety Research. - : Dept. of Technology & Society, Faculty of Engineering, LTH, Lund University. - 2004-3082. ; 3
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Journal article (peer-reviewed)abstract
- The study presents a simple and easy to implement method for detection of the evasive action start in traffic interactions. The method is based on comparison of the studied trajectory with a reference set of ‘unhindered’ trajectories, interpreting the start of evasive action as the moment when no more similarities can be found. The suggested algorithm performs well for primary interactions when road users arrive in an unhindered state. It fails, however, in case of secondary interactions. Explorative application of the method on a large dataset of normal and conflict traffic situations concludes that traffic conflicts occur more frequently in secondary interactions, presumably due to higher cognitive load on the involved road users. Despite the limitations, the method can be used both for the safety studies based on traffic conflicts and for more general quantification and visualisation of the road user behaviour.
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| 10. |
- Johnsson, Carl
(author)
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Surrogate Measures of Safety with a Focus on Vulnerable Road Users : An exploration of theory, practice, exposure, and validity
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Surrogate measures of safety (SMoS) are meant to function as tools to investigate traffic safety. The term surrogate indicates that these measures do not rely on crash data; instead, they focus on identifying safety critical events (or near-crashes) in traffic, which can be used as an alternative to crash records. The overall aim of this thesis is to explore which SMoS are suitable when analysing the safety of vulnerable road users (pedestrians and cyclists). The thesis attempts to answer this question using two different approaches: 1) a literature review focusing on existing surrogate measures and how well they consider vulnerable road users from a theoretical perspective, and 2) four observational studies which focus on the validity of SMoS and their relation to exposure.The literature review focuses on identifying existing SMoS, and on two main aspects when evaluating their suitability for analysing the safety of vulnerable road users. Firstly, if the indicators theoretically are able to measure both the risk of collision and the potential for injury should a collision occur, and secondly, to what extent vulnerable road users were included in previous validation studies. The findings from the literature review are that the most commonly used indicators (Time to Collision Minimum and Post Encroachment Time) are also the most validated, but that they have several theoretical limitations, mainly that they to do not measure injury potential and that they measure the severity of an event based on the outcome rather than the initial conditions or potential/observed evasive actions. There are also several indicators which theoretically are more suitable but instead lack validation studies.The observational studies, which make up the second part of this thesis, consist of an attempt at a large-scale validation study, followed by several studies which focus on the shortcomings discovered in the first attempt. The large-scale study is based on three weeks of video recordings made at 26 signalized intersections in seven European countries. The analysis of these videos resulted in three major findings. Firstly, the lack of comparable crash records made any large-scale validation attempts impossible. Secondly, the lack of comparability between the critical events identified by human observers and those identified by computer calculations made it infeasible to perform a long-term analysis. Thirdly, there is a significant relationship between meetings and critical events identified using Time to Collision Minimum and Post Encroachment Time, which suggests that some of the benefit of using those (and other indicators) might originate from their inherent connection to simple meetings between road users (i.e. exposure). Following these results, the thesis presents a limited validation study based solely on the Scandinavian intersections followed by a suggestion for how a relative approach to validity might offer a potentially easier way of evaluating SMoS in the future. The results from these studies indicate that Time to Collision Minimum can measure safety to at least some extent, while Post Encroachment Time measures it to a lesser extent. Due to the strong connection between critical events and meetings, the thesis also explores how a meeting between road users can be defined and how understanding what constitutes an opportunity for a crash might help to explain the so-called safety-in-numbers effect, as well as how future SMoS studies should consider meetings.
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