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

Safe system learning for tertiary road transport engineering students

Context: The Safe System philosophy, adopted in many countries and underpinning Australian and New Zealand road safety strategy, is best-practice in road safety. However, there remains a general absence of the Safe System approach in many road transport engineering undergraduate courses. Despite being acknowledged as best-practice, little of the Safe System is known by graduating engineers, creating a discrepancy between base graduate knowledge and road safety industry practice which is a problem for industry. Purpose: The aim of this project is to determine the best educational design for disseminating Safe System learnings to tertiary engineering students. This paper will explore the best educational design for: a. Disseminating Safe System moral and ethical principles for all tertiary engineering students particularly in fields where human safety is considered paramount. b. Disseminating Safe System theory and practice for tertiary engineering students focussing on road transport engineering. Approach: Responding to the road transportation industry need to recruit engineers versed in the Safe System, curriculum guidelines and materials are being developed to guide Safe System learning at the tertiary level. Graduate attributes and learning outcomes are developed with input from industry representatives. The approaches to learning and teaching are developed with the assistance of senior teaching academics. Key objectives of the approach are modular topics and material for ease of integration into existing courses; interactive teaching material based on industry knowledge and case studies; and a thematic learning approach. Results: The Safe System for Universities (SS4U) curriculum guideline is being developed as a guideline for the learning and teaching of Safe System ethical and moral principles at an introductory level for first year engineering students, and Safe System theory and practice at a more advanced level for students undertaking study in road transportation engineering. It will provide road transport engineering students with the information needed to critically analyse the discussion and application of Safe System thinking and importantly, to be able to question when it is absent. Furthermore, the broad moral and ethical principles of engineering safety are emphasized to enable engineering students a moral and ethical perspective to the technical and procedural decisions that they will make in their future careers. Conclusions: Through this project, a means for smarter educational design for disseminating Safe System knowledge to student engineers is being developed. The outcome of this dissemination will be graduate engineers able to apply their knowledge of the Safe System to their chosen field of practice to benefit the wider community, and specifically, helping to fulfil a road transport industry need.Christopher Stokes, Wayne Moon, Johan Strandroth, Jeremy Woolley, Niclas Johansso

The Correlation Between Pedestrian Injury Severity in Real-Life Crashes and Euro NCAP Pedestrian Test Results

Objective: The aim of the present study was to estimate the correlation between Euro NCAP pedestrian rating scores and injury outcome in real-life car-to-pedestrian crashes, with special focus on long-term disability. Another aim was to determine whether brake assist (BA) systems affect the injury outcome in real-life car-to-pedestrian crashes and to estimate the combined effects in injury reduction of a high Euro NCAP ranking score and BA. Methods: In the current study, the Euro NCAP pedestrian scoring was compared with the real-life outcome in pedestrian crashes that occurred in Sweden during 2003 to 2010. The real-life crash data were obtained from the data acquisition system Swedish Traffic Accident Data Acquisition (STRADA), which combines police records and hospital admission data. The medical data consisted of International Classification of Diseases (ICD) diagnoses and Abbreviated Injury Scale (AIS) scoring. In all, approximately 500 pedestrians submitted to hospital were included in the study. Each car model was coded according to Euro NCAP pedestrian scores. In addition, the presence or absence of BA was coded for each car involved. Cars were grouped according to their scoring. Injury outcomes were analyzed with AIS and, at the victim level, with permanent medical impairment. This was done by translating the injury scores for each individual to the risk of serious consequences (RSC) at 1, 5, and 10 percent risk of disability level. This indicates the total risk of a medical disability for each victim, given the severity and location of injuries. The mean RSC (mRSC) was then calculated for each car group and t-tests were conducted to falsify the null hypothesis at p <= .05 that the mRSC within the groups was equal. Results: The results showed a significant reduction of injury severity for cars with better pedestrian scoring, although cars with a high score could not be studied due to lack of cases. The reduction in RSC for medium-performing cars in comparison with low-performing cars was 17, 26, and 38 percent for 1, 5, and 10 percent of medical impairment, respectively. These results applied to urban areas with speed limits up to 50 km/h, although no significant reduction was found in higher speed zones. Regarding cars with BA, the null hypothesis could not be rejected at p = .05; hence, no significant results of injury reduction were found. Conclusions: A significant correlation between Euro NCAP pedestrian score and injury outcome in real-life car-to-pedestrian crashes was found. Injury reduction was found to be higher with increasing severity and level of permanent medical impairment. The difference between 1- and 2-star cars is 17 percent in mean risk of permanent medical impairment (mRSC) 1%+, 26 percent in mRSC 5%+, and 38 percent in mRSC 10%+ for crashes in speed zones up to 50 km/h. Brake assist was not found to provide a statistically significant injury reduction

Safe System for Universities: linking graduate knowledge with industry best practice

Safe System represents long-established best-practice in road safety internationally, in Australia and in New Zealand. However, there has been limited success in implementing Safe System policy into practice. While Safe System theory is taught at some Australian universities, there are currently no consistent means of formal education before professionals enter the workforce, leading to a discrepancy between graduate engineer knowledge and industry best-practice. The Safe System for Universities (SS4U) project provides a means for consistent education of Safe System theory at a tertiary level. SS4U is designed for self-learning and a curriculum and material to teach Safe System within existing courses.Chris Stokes, Wayne Moon, Jeremy Woolley, Johan Strandroth, Niclas Johansso

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

This was the first retrospective study to estimate the effect of increased pedestrian protection, autonomous emergency braking, 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 (Strada), where information of road traffic crashes between passenger cars and pedestrians or bicyclists for the period 1 January 2003–31 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 (AIS) 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. Although many results were found to be statistically non-significant, the following results were found to be significant at least at 90% level. Pedestrian mRPMI10%+ was reduced by 44% in speed zones ≤ 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. For cyclists, the mRPMI10%+ was reduced by 35% in speed zones ≤ 50 km/h. For crashes within ± 20 meters from a pedestrian or bicycle crossing, the AEB system reduced 60% 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 points) in the NCAP pedestrian test and cars with a high score (28–36 points) showed that pedestrian mRPMI10%+ was reduced by 48% 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 ≤ 30 km/h speed limit (-73%) and across all speed limits (-36%). Including only those aged ≤ 64 years, the reduction was 49%. 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 an active bonnet. The STA safety rating of pedestrian and bicycle crossings showed that overall pedestrian mRPMI1%+ was reduced by 15%, while cyclists mRPMI10%+ was reduced by 32% 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%, 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, can create significant reductions of serious (long-term) injuries among pedestrians and bicyclists. © 2024, Lund University Faculty of Engineering. All rights reserved