Claes Tingvall

The Effectiveness of Electronic Stability Control (ESC) in Reducing Real Life Crashes and Injuries

Electronic Stability Control (ESC) was introduced on the mass market in 1998. Since then, several studies showing the positive effects of ESC have been presented. Objective. In this study, data from crashes occurring in Sweden during 1998 to 2004 were used to evaluate the effectiveness of ESC on real life crashes. The effectiveness was analyzed for different road conditions, and some accident types and injury levels. Methods. The study used statistical analysis. To control for exposure, induced exposure methods were used, where ESC-sensitive to ESC-insensitive crashes and road conditions were matched in relation to cars equipped with and without ESC. Cars of similar or, in some cases, identical make and model were used to isolate the role of ESC. Results. The study shows a positive and consistent effect of ESC overall and in circumstances where the road has low friction. The overall effectiveness on all injury crash types, except rear end crashes, was 16.7 ± 9.3%, while for serious and fatal crashes; the effectiveness was 21.6 ± 12.8%. The corresponding estimates for crashes with injured car occupants were 23.0 ± 9.2% and 26.9 ± 13.9%. For serious and fatal loss-of-control type crashes on wet roads the effectiveness was 56.2 ± 23.5% and for roads covered with ice or snow the effectiveness was 49.2 ± 30.2%. It was estimated that for Sweden, with a total of 500 vehicle related deaths annually, that 80–100 fatalities could be saved annually if all cars had ESC. Conclusions. ESC was found to reduce crashes with personal injuries, especially serious and fatal injuries. The effectiveness ranged from at least 13% for car occupants in all types of crashes with serious or fatal outcome to a minimum of 35% effectiveness for single/oncoming/overtaking serious and fatal crashes on wet or icy road surface. No difference in deformation pattern was found for cars with or without ESC.

The use of seat belts in cars with smart seat belt reminders--results of an observational study

Recently, smart seat belt reminders (SBR) have been introduced in cars. By increasingly reminding drivers and passengers if they are not using the seat belt, the intention is to increase the belt use to almost 100%. Objective. The objective was to study if there were differences in drivers seat belt use between cars with and without SBR. Methods. Drivers of cars with and without SBR were observed concerning seat belt use. The case (cars with SBR) and the control group (cars without SBR) were similar in all major aspects except SBR. In all, more than 3,000 drivers were observed in five cities in Sweden. Results. In cars without SBR, 82.3 percent of the drivers used the seat belt, while in cars with SBR, the seat belt use was 98.9 percent. The difference was significant. In cars with mild reminders, the use was 93.0 percent. Conclusion. It is concluded, that if the results can be generalised to the whole car population this would have a dramatic impact on the number of fatally and seriously injured car occupants.

Intelligent Seat Belt Reminders—Do They Change Driver Seat Belt Use in Europe?

Objective. Many modern cars have seat belt reminders (SBRs) using loud and clear sound and light signals. These systems have developed over the last few years. This study investigates how these modern systems influence the seat belt use in real-life traffic in built-up areas in some European cities. Methods. The data were collected by field observations in major cities in six European countries and in five cities around Sweden. A selection of car models having seat belt reminders (SBR) were compared to a fleet of similar car models without such reminders. Results. A significant difference in seat belt wearing rate was found in the cars with seat belt reminders. For all observations, the total seat belt wearing rate was 97.5% +/− 0.5% in cars with SBR, while it was 85.8% +/− 0.8% in cars without. There were differences in seat belt use in the different observation locations. The lowest seat belt use was found in Brussels/Belgium with a use rate of 92.6 +/− 2.2% in cars with seat belt reminders and 69.6 +/− 3.1% in cars not fitted with reminders. The highest seat belt use was found in Paris/France where 99.8 +/− 0.4% of the drivers used the seat belt in cars with reminders and 96.9 +/−1.1% were belted in cars without reminders. Conclusion. Seat belt reminders fulfilling Euro NCAPs seat belt reminder protocol are increasing the seat belt use in daily traffic significantly. Around 80% (82.2% +/− 8.6%) of the drivers not putting the belt on without a seat belt reminder do so in cars equipped with an SBR that has a light signal and an associated loud and clear sound signal.

Use of Fatal Real-Life Crashes to Analyze a Safe Road Transport System Model, Including the Road User, the Vehicle, and the Road

Objective. To evaluate if the Swedish Road Administration (SRA) model for a safe road transport system, which includes the interaction between the road user, the vehicle, and the road, could be used to classify fatal car crashes according to some safety indicators. Also, to present a development of the model to better identify system weakness. Methods. Real-life crashes with a fatal outcome were classified according to the vehicles safety rating by Euro NCAP (European Road Assessment Programme) and fitment of ESC (Electronic Stability Control). For each crash, the road was also classified according to EuroRAP (European Road Assessment Programme) criteria, and human behavior in terms of speeding, seat belt use, and driving under the influence of alcohol. Each crash was compared with the model criteria, to identify components that might have contributed to fatal outcome. All fatal crashes where a car occupant was killed that occurred in Sweden during 2004 were included: in all, 215 crashes with 248 fatalities. The data were collected from the in-depth fatal crash data of the Swedish Road Administration (SRA). Results. It was possible to classify 93% of the fatal car crashes according to the SRA model. A number of shortcomings in the criteria were identified since the model did not address rear-end or animal collisions or collisions with stationary/parked vehicles or trailers (18 out of 248 cases). Using the further developed model, it was possible to identify that most of the crashes occurred when two or all three components interacted (in 85 of the total 230 cases). Noncompliance with safety criteria for the road user, the vehicle, and the road led to fatal outcome in 43, 27, and 75 cases, respectively. Conclusions. The SRA model was found to be useful for classifying fatal crashes but needs to be further developed to identify how the components interact and thereby identify weaknesses in the road traffic system. This developed model might be a tool to systematically identify which of the components are linked to fatal outcome. In the presented study, fatal outcomes were mostly related to an interaction between the three components: the road, the vehicle, and the road user. Of the three components, the road was the one that was most often linked to a fatal outcome.