The effects of studded tires on fatal crashes with passenger cars and the benefits of electronic stability control (ESC) in Swedish winter driving

• This study set out to examine the effects of studded tires on fatal crashes on roads covered with ice orsnow in Sweden and also to investigate the extra benefits of electronic stability control (ESC) during thewinter months. Two different studies are presented in this paper. Both studies used an induced exposureapproach. In the main study, 369 in-depth studies of fatal crashes with passenger cars were analyzed todetermine whether loss-of-control (LOC) had been a major component or not. Only crashes involving carswithout ESC and equipped with approved studded or non-studded winter tires were analyzed. The additionalstudy used police-reported crashes that occurred during the winter seasons 2003–2010, involvingpassenger cars with and without ESC. While police records in Sweden do not include any tire information,it was assumed that most cars involved in crashes during the winter period would be equipped withstudded tires.Findings in the main study showed that in 64% of the fatal crashes on roads covered with ice or snowLOC had been a major component. Furthermore, in 82% of LOC crashes, the passenger car over-steeredprior to collision. Studded tires were found to have a statistically significant effect of 42% in terms of fatalcrash reduction on roads covered with ice or snow, compared to non-studded winter tires. The effecton dry or wet roads in the winter was negative, although statistically non-significant. In the additionalstudy, it was found that ESC further reduced crashes with injuries by 29%. The benefits on severe andfatal crashes were slightly greater (32%), although the lower 95% confidence limit was lower.Although studded tires were shown to reduce the risk of fatal crash involvement, compared to nonstuddedwinter tires, the proportion of LOC and over-steering among cars with studded tires was large(59% and 49%, respectively). It was therefore concluded that studded tires do not prevent all LOC crashes,while ESC has benefits in those crashes since this technology mostly addresses over-steering. This is alsosupported by the fact that the share of LOC fatal crashes is considerably lower for ESC-equipped cars.This study recommends that non-ESC cars should be fitted with studded tires if they are to be drivenon roads covered by ice or snow. If the proportion of studded tires is to be decreased on Swedish roads toreduce the about of hazardous particulates especially in built up areas, from a road safety point of viewit is recommended that this should be done in phase with the implementation of ESC on all passengercars.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

Nyckelord

winter tires

fatal crashes

ESC

Studded tires

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)