Characteristics of future crashes in Sweden – identifying road safety challenges in 2020 and 2030

It has been proposed by the European Commission that the number of road fatalities within the European Union should move close to zero by 2050. In response to that, Sweden has set out to revise the national road safety targets of 2020 and 2030. In order to address future safety challenges, there is a need to consider the characteristics of future crashes. The objective of this study was therefore to quantify and investigate the characteristics of severe crashes in 2020 and 2030. Injury crashes were reduced from a baseline in 2014 to a given time in the future based on the implementation of safety interventions. The material consisted of hospital admission data with AIS diagnoses. Results show that the actions planned to be taken in Sweden between now and 2020 and 2030 will continue to increase the safety level for car occupants, but are estimated to be insufficient for vulnerable road users. It was concluded that there is a need to define a safety system for vulnerable road users that takes a holistic approach to sustainability by including both injury prevention measures and measures to encourage more health-promoting and fossil-free modes of transport

The safety effect of increased pedestrian protection, autonomous emergency braking for pedestrians and bicyclists on passenger cars, and speed management

The overall objective of this paper was to estimate the effect of increased pedestrian protection and speed management to reduce serious injuries among pedestrians and bicyclists. More specifically, the aim was to estimate the injury mitigating effects of the following interventions: AEB with pedestrian and bicyclist detection, Euro NCAP pedestrian test score, Active Bonnet, Traffic calming at pedestrian and bicycle crossings, and additionally, the combined effect of the above-mentioned treatments. The main source of data was the Swedish traffic data acquisition system, where information of road traffic crashes between passenger cars and pedestrians or bicyclists for the period January 2003–December 2022 was obtained. Cars with optional fitment of AEB systems were identified, and the license registration number was used to access individual car equipment lists to identify whether the vehicle was equipped with AEB with pedestrian and/or cyclist detection. Information about traffic calming at pedestrian and bicycle crossings was obtained from the Swedish Transport Administration. The injury metric used was risk of permanent medical impairment (RPMI) of at least one percent and ten percent. RPMI captures the risk of long-term medical impairment based on a diagnosed injury location and Abbreviated Injury Severity score. The relative difference between the mean values of RPMI (mRPMI1% and mRPMI10%+) was calculated and tested using an independent two sample t-test which was conducted for unequal sample sizes and variance. Pedestrian mRPMI10%+ was reduced by 34%–44% in speed zones 10–50 km/h comparing the group struck by cars equipped with AEB with pedestrian detection compared to the group struck by cars without the system. However the reduction was only significant at 90% level. The pattern was similar also for mRPMI1%+. For cyclists, the mRPMI10%+ was reduced by 35% at speed zones 10–50 km/h. For crashes within +/- 20 meters from a pedestrian or bicycle crossing, the AEB system reduced 60% (p = 0.05) of pedestrians mRPMI10%+ at crossings with good safety standard compared to crossings of poor safety standard. The comparison of cars with poor performance (1–9 p) in the NCAP pedestrian test and cars with a high score (28–36 p) showed that pedestrian mRPMI10%+ was reduced by 48% (p < 0.01) across all speed limits, and by 64% including only those aged ≤ 64 years. For bicyclists, a significant reduction of cyclist mRPMI10%+ was found comparing low scoring cars to high scoring cars in 10–30 km/h speed limit (-73%, p = 0.02) and across all speed limits (-36%, p = 0.06). Including only those aged ≤ 64 years, the reduction was 49% (p < 0.01). For the active bonnet, a significant reduction of mRPMI1%+ by 24% was observed but given that the rate of helmet wearing was higher in the group struck by cars with active bonnet, this difference cannot be attributed to an effect of the active bonnet. The STA safety rating of pedestrian and bicycle crossings showed that overall pedestrian mRPMI1%+ was reduced by 15% (p = 0.06), while cyclists mRPMI10%+ was reduced by 32% (p = 0.01) comparing crossings of high safety level to crossings of poor safety level. The analysis of combined interventions showed that the total reduction of pedestrians and cyclists mRPMI10%+ together was 69% (p < 0.01), from 6.4% to 2%. This paper demonstrates that a road environment with adapted infrastructure and speed, combined with passenger car technologies that improve the safety for vulnerable road users, creates significant reductions of serious injuries among pedestrians and bicyclists

A Method to Identify Future Potential of Vehicle Safety Technology

In the design of a safe road transport system there is a need to better understand the safety challenges lying ahead. One way of doing that is to evaluate safety technology with retrospective analysis of real world crashes. However, by using retrospective data there is the risk of adapting safety innovations to scenarios irrelevant in the future. Also, challenges arise as safety interventions do not act alone but are rather interacting components in a complex road transport system and there exists no linearity between the development of Safety Performance Indicators in traffic and in the final outcome in terms of health losses. This thesis is based on two papers from studies aiming to increase the knowledge in this field by (1) developing and applying a new method to identify future potential of vehicle safety technology in Sweden, and (2) estimate the potential benefits of Autonomous Emergency Braking (AEB) in head-on crashes between passenger cars and heavy-goods vehicles. The first study relates to the need for new prediction models, while the second relates to the need for further understanding how different crash scenarios determines the input and output in different parts in the chain of events leading to a crash, e.g. the integrated safety chain, and thereby affects the performance of safety systems.The key point in study 1 was to project the integrated safety chain in crashes of today into the crashes for a given time in the future. Assumptions on the implementation of safety technologies were made as applied to fatal passenger-car crashes of today. It was estimated which crashes would be prevented and the residual were analyzed to identify the characteristics of future crashes. The study predicts that the number of car occupants killed would be reduced by 53% from 2010 to 2020. Through this new method, valuable information regarding the characteristic of the future crashes could also be found. In study 2 calculations of the available time for AEB depending on crash scenario were done in order to estimate the potential benefits of AEB. The findings indicates that there is a great safety potential in applying AEB in head-on scenarios even late in the integrated safety chain, when the collision is no longer avoidable by steering. It also confirmed that the available time for AEB, and thereby the effect of AEB in delta-v reduction, is highly dependent on the scenarios prior to the point of braking. Application of the combined results from paper 1 and paper 2 can be exemplified in that paper 1 predicts a reduction of loss-of-control scenarios and paper 2 shows that this specific scenario provides the shortest time available for autonomous emergency braking. Thus, there are indications that AEB could have a greater safety potential in the future as loss-of-control scenarios are decreasing over time. Even though more knowledge is required, these interactions and possible systems effects highlights the potential in having an holistic approach when evaluating vehicle safety technologies and their future benefits

Identifying the Potential of Combined Road Safety Interventions - A Method to Evaluate Future Effects of Integrated Road and Vehicle Safety Technologies

Health loss in the road transport system is one of the leading global public health problems with approximately 1.3 million people killed annually. In order to have a systematical approach to improved road safety, it has become common practice to form road safety management policies that include target setting and evaluation. The overall aim of this thesis was to facilitate road safety management by developing a new method to guide stakeholders with decisions on the most effective interventions to improve road safety, or in the design of safety innovations.In this thesis, a new method to identify the potential of combined road safety interventions was developed and validated. Crashes were studied from a system’s approach perspective, and the integrated safety chain was used to derive a residual of crashes from a baseline based on assumptions regarding the progress of Safety Performance Indicators over the period studied. The characteristics of the residual fatal crashes in 2020 were then described and analyzed to identify future safety gaps. A validation of the method was conducted by taking into account actual interventions implemented between 2000 and 2010 and by reducing the fatalities in 2000 to a residual of crashes in 2010 and then comparing this to the true outcome of 2010. It was concluded that the method was found to give an overall valid explanation for the reduction of fatalities from 2000 to 2010.The main advantage of this method compared to previous methods is the ability to describe the characteristics of future crashes, and what measures would be effective in reducing them. Single vehicle and head-on crashes were estimated to be reduced most significantly from 2000 to 2010, largely as a result of the installation of median barriers and the fitment of Electronic Stability Control. In two studies, effect estimates of pedestrian friendly car fronts and Autonomous Emergency Braking (AEB) fitted on Heavy Goods Vehicles in head-on crashes were derived and these estimates can be applied in the method in future. It was also concluded that positive system effects can emerge between road and vehicle safety technologies. Speed management can enhance the performance of pedestrian protection which will be important for increasing safety for vulnerable road users. In addition, it was found that the overall effectiveness of AEB would increase if the proportion of loss-of-control scenarios is minimalized and that AEB could be very helpful for increasing the compatibility between passenger cars and Heavy Goods Vehicles.This thesis presents a new approach to evaluating future effects of integrated road and vehicle safety technologies. It can be summarized as; 1 – Highlight future potentials and safety gaps, 2 – Define and refine technological innovations and 3 – Guiding integrated interventions. It is recommended that the evolution of the transport system is taken into account when estimating the benefits of future technologies. Road and vehicle safety interventions should be designed in collaboration with stakeholders and combined in the best possible way in order to create positive system effects. There is also a need for accurate effect estimates as they form essential tools in the road safety management process

Identifying the Potential of Combined Road Safety Interventions - A Method to Evaluate Future Effects of Integrated Road and Vehicle Safety Technologies

Health loss in the road transport system is one of the leading global public health problems with approximately 1.3 million people killed annually. In order to have a systematical approach to improved road safety, it has become common practice to form road safety management policies that include target setting and evaluation. The overall aim of this thesis was to facilitate road safety management by developing a new method to guide stakeholders with decisions on the most effective interventions to improve road safety, or in the design of safety innovations.In this thesis, a new method to identify the potential of combined road safety interventions was developed and validated. Crashes were studied from a system’s approach perspective, and the integrated safety chain was used to derive a residual of crashes from a baseline based on assumptions regarding the progress of Safety Performance Indicators over the period studied. The characteristics of the residual fatal crashes in 2020 were then described and analyzed to identify future safety gaps. A validation of the method was conducted by taking into account actual interventions implemented between 2000 and 2010 and by reducing the fatalities in 2000 to a residual of crashes in 2010 and then comparing this to the true outcome of 2010. It was concluded that the method was found to give an overall valid explanation for the reduction of fatalities from 2000 to 2010.The main advantage of this method compared to previous methods is the ability to describe the characteristics of future crashes, and what measures would be effective in reducing them. Single vehicle and head-on crashes were estimated to be reduced most significantly from 2000 to 2010, largely as a result of the installation of median barriers and the fitment of Electronic Stability Control. In two studies, effect estimates of pedestrian friendly car fronts and Autonomous Emergency Braking (AEB) fitted on Heavy Goods Vehicles in head-on crashes were derived and these estimates can be applied in the method in future. It was also concluded that positive system effects can emerge between road and vehicle safety technologies. Speed management can enhance the performance of pedestrian protection which will be important for increasing safety for vulnerable road users. In addition, it was found that the overall effectiveness of AEB would increase if the proportion of loss-of-control scenarios is minimalized and that AEB could be very helpful for increasing the compatibility between passenger cars and Heavy Goods Vehicles.This thesis presents a new approach to evaluating future effects of integrated road and vehicle safety technologies. It can be summarized as; 1 – Highlight future potentials and safety gaps, 2 – Define and refine technological innovations and 3 – Guiding integrated interventions. It is recommended that the evolution of the transport system is taken into account when estimating the benefits of future technologies. Road and vehicle safety interventions should be designed in collaboration with stakeholders and combined in the best possible way in order to create positive system effects. There is also a need for accurate effect estimates as they form essential tools in the road safety management process

Validation of a method to evaluate future impact of road safety interventions, a comparison between fatal passenger car crashes in Sweden 2000 and 2010

When targeting a society free from serious and fatal road-traffic injuries, it has been a common practice in many countries and organizations to set up time-limited and quantified targets for the reduction of fatalities and injuries. In setting these targets EU and other organizations have recognized the importance to monitor and predict the development toward the target as well as the efficiency of road safety policies and interventions. This study aims to validate a method to forecast future road safety challenges by applying it to the fatal crashes in Sweden in 2000 and using the method to explain the change in fatalities based on the road safety interventions made until 2010. The estimation of the method is then compared to the true outcome in 2010. The aim of this study was to investigate if a residual of crashes produced by a partial analysis could constitute a sufficient base to describe the characteristics of future crashes. Result: show that out of the 332 car occupants killed in 2000, 197 were estimated to constitute the residual in 2010. Consequently, 135 fatalities from 2000 were estimated by the model to be prevented by 2010. That is a predicted reduction of 41% compared to the reduction in the real outcome of 53%, from 332 in 2000 to 156 in 2010. The method was found able to generate a residual of crashes in 2010 from the crashes in 2000 that had a very similar nature, with regards to crash type, as the true outcome of 2010. It was also found suitable to handle double counting and system effects. However, future research is needed in order to investigate how external factors as well as random and systematic variation should be taken into account in a reliable manner

Road Safety Analysis

AbstractRoad safety analysis can be used to understand what has been successful in the past and what needs to be changed in order to be successful to reduce severe road trauma going forward and ultimately what’s needed to achieve zero. This chapter covers some of the tools used to retrospectively evaluate real-life benefits of road safety measures and methods used to predict the combined effects of interventions in a road safety action plan as well as to estimate if they are sufficient to achieve targets near-term and long-term. Included are also a brief overview of methods to develop boundary conditions on what constitutes a Safe System for different road users. Further to that, the chapter lists some arguments for the need of high-quality mass and in-depth data to ensure confidence in the results and conclusions from road safety analysis. Finally, a few key messages are summarized.</jats:p

Avancerade förarassistanssystem (ADAS) i dödsolyckor med personbilar

Slutrapporten är framtagen med ekonomiskt stöd från Trafikverket Skyltfonden. Ståndpunkter, slutsatser och arbetsmetoder i rapporten reflekterar författaren och överensstämmer inte med nödvändighet med Trafikverkets ståndpunkter, slutsatser och arbetsmetoder inom rapportens ämnesområde.  Projektets övergripande syfte var att undersöka moderna bilar med avancerade förarstödsystem (ADAS) inblandning i vägtrafikolyckor med dödlig utgång. Specifikt undersöktes följande frågeställningar;  1. Hur stor andel av personbilar inblandade i dödsolyckor har ett ADAS system av nivå 0–2? 2. Vilka säkerhetssystem finns bland bilar inblandade i dödsolyckor? 3. Vilka omständigheter med betydelse för funktionen av autobroms eller kurshållningsassistans (tex hastighet, ljusförhållanden) har funnits i olyckor där ett dödsfall skett trots att bilen haft en för olyckan relevant system? 4. Finns exempel på avvikelser där en bil haft autobroms eller kurshållningsassistans som borde haft en inverkan på förloppet, men där ett dödsfall ändå skett?   5. Kan man kvantifiera effekten av kurshållningsassistans och autobroms med detektion av fotgängare och/eller cyklister? 6. Hur kan vägmiljön optimeras för att öka effekten av kurshållningsassistans och autobroms?  Studien bygger på Trafikverkets djupstudier av dödsolyckor. Sedan 1997 har Trafikverket genomfört djupstudier av dödsolyckor i vägtrafiken. Målet med en olycksutredning är att förstå varför en olycka resulterat i ett dödsfall och vad som kan göras på systemnivå för att förhindra liknande dödsolyckor i framtiden. I händelse av en dödsolycka samlas information in om vägmiljön, fordonet och personen/personerna i olyckan. Man genomför en platsundersökning och dokumenterar olycksplatsen och inblandade fordon. Materialet bestod av 443 dödsolyckor som inträffat mellan 2014–2023 där en personbil av årsmodell 2014 eller senare varit inblandad. Analysen visade att i 274 fall (62 %) hade en bil minst ett ADAS-system. Baserat på de resultat som framkommit av studien drar vi följande slutsatser;  • Det var vanligt att äldre personer blivit påkörda av bilar med AEB för fotgängare i lägre hastigheter där systemet normalt förväntas fungera, och hälften av alla påkörda fotgängare blev påkörda i hastigheter högre än vad som normalt förväntas att systemet är effektivt. Därför behöver AEB med detektion av fotgängare och/eller cyklister förbättras för att fungera bättre och i högre hastigheter än idag, samt att hastigheten för bilar ska begränsas och vara låg på vägar där fotgängare kan korsa.  • Scenarion med upphinnande mot tunga fordon bör inkluderas i Euro NCAPs testprotokoll för AEB samt att alla AEB system testas för i högre hastigheter.  • Det var många dödsfall som skett i olyckor där en bil med kurshållningsassistans kommit ur sitt körfält eller kört av vägen. Därför borde kurshållningsassistans testas i Euro NCAP i fler kritiska situationer och körsätt, tex vid kurviga vägar och kraftig acceleration, för att driva utvecklingen mot att systemet kan vara effektivt i fler kritiska situationer.  • Även med dagens moderna bältespåminnare omkommer personer obältade, därför bör system som bättre kan upptäcka obältade eller felanvändning av bälte utvecklas.   • I framtiden bör bilar vara utrustade med teknik som upptäcker försämrad förarförmåga, till exempel på grund av alkohol, samt på ett mer ingripande sätt kunna begränsa hastigheten till åtminstone hastighetsgränsen.  Den erhållna trafiksäkerhetsnyttan av studien är förslag kring överväganden för väghållare när det kommer till vägmiljön och dess betydelse för fordon med avancerade stödsystem samt förslag på att vidareutveckla tester i Euro NCAP till att innefatta fler scenarion och högre hastigheter

Trafikskador ur ett genusperspektiv : En kartläggning av män och kvinnors trafikskador inom olika färdsätt

Denna rapport har finansierats av Vägverkets Skyltfond. Uppdragsansvarig är Vägverket Konsult genom Johan Strandroth. Rapporten är författad av Emely Knudsen, Johan Strandroth och Jenny Eriksson. Studien syftar till att med hjälp av uppgifter om trafikskador från sjukvården registrerade i STRADA kartlägga skillnader mellan män och kvinnors trafikskador

Injury measures describing health loss from traffic crashes : how is the prioritization of traffic safety work affected?

Målstyrning är en grundläggande del av trafiksäkerhetsarbetet och hur målet definieras har en direkt koppling till vilka strategier som används för att nå målen. I Sveriges målstyrning är det antalet omkomna och allvarligt skadade personer som följs upp. Som allvarligt skadad definieras den som i samband med en vägtrafikolycka fått en skada som ger minst en procents permanent medicinsk invaliditet.  Syftet med denna rapport har varit att öka förståelsen för hur trafiksäkerhetsarbetets prioriteringar gällande allvarligt skadade skulle påverkas om man använde andra skademått än medicinsk invaliditet. I rapporten jämförs måtten PMI 1+ (grunden till dagens definition för allvarligt skadad), och PMI 10+ (mycket allvarligt skadad) med funktionsjusterade levnadsår (YLD) enligt DALY och MAIS 3+ som är den EU-gemensamma definitionen för svårt skadad.  Data som ligger till grund för beräkningarna består av alla skadade personer rapporterade i Strada sjukvård under 2018 och 2019, totalt 63 587 personer. Jämförelser görs mellan de olika skademåtten avseende skillnader i risk för olika trafikantgrupper, fördelning av åldersgrupper, olyckstyper, trafikmiljöer och skadefördelning.  Resultaten visar bland annat att skademåtten PMI 1+, PMI 10+ och MAIS 3+ ger en liknande bild över fördelningen av vilka som skadas, och i vilka olyckor och trafikmiljöer, men att storleks[1]ordningen på antalet skadade skiljer sig åt. Bland dessa skademått är den största gruppen skadade cyklister i tättbebyggt område (eller fotgängare i fallolyckor om dessa inkluderas). Om YLD används skulle istället den största delen av hälsoförlusterna komma från personer som skadats i personbil utanför tätort.Management by objectives is a fundamental part of road safety. How the goal is defined has a direct connection to which strategies are used to reach the set goals. In Sweden, the target is defined as the number of fatalities and seriously injured in the road transport system. A seriously injured is defined as someone who, in connection with a road traffic crash, has suffered an injury that results in at least one percent permanent medical impairment.  The aim of this study was to increase the understanding on how priorities in road safety would be affected if other injury measures than medical disability would be used. The report compares the measures PMI 1+ (the basis of today’s definition of seriously injured), and PMI 10+ with disability adjusted life years (YLD) according to DALY and MAIS 3+, which is the definition of severely injured used in the EU.  The data that forms the basis of the calculations consists of all injured persons reported in the Swedish national accident database, Strada, during 2018 and 2019, a total of 63,587 persons. Comparisons are made between the different injury measures regarding differences in risk for different road user groups, distribution of age groups, accident types, traffic environments and injury distribution.  The results show that the injury measures PMI 1+, PMI 10+ and MAIS 3+ provides a similar picture of the distribution of who is injured, and in which crashes and traffic environments, but that the order of magnitude of the number of injured differ. Among these injury measures, the largest group of injured are cyclists in urban areas (or pedestrians in fall accidents if these are included). If YLD is used, the largest part of health losses would instead come from people who were injured in passenger cars outside urban areas