Injury risk curves to guide safe speed limits on Swedish roads using German crash data supplemented with estimated non-injury crashes
Artikel i vetenskaplig tidskrift, 2024

Vision Zero postulates that no one should be killed or seriously injured in road traffic; therefore, it is necessary to define evidence-based speed limits to mitigate impact severity. The overall aims to guide the definition of safe speeds limits by establishing relations between impact speed and the risk of at-least-moderate (MAIS2+) and at-least-severe (MAIS3+) injuries for car occupants in frontal and side crashes in Sweden. As Swedish in-depth data are unavailable, the first objective was to assess the applicability of German In-depth Accident Study (GIDAS) data to Sweden. The second was to create unconditional injury risk curves (risk of injury given involvement in any crash), rather than risk curves conditional on the GIDAS sampling criterion of suspected-injury crashes. Thirdly, we compared the unconditional and conditional risk curves to quantify the practical implications of this methodological choice. Finally, we provide an example to demonstrate how injury risk curves facilitate the definition of safe, evidence-based speed limits in Sweden. Characteristics important for the injury outcome were similar between GIDAS and Swedish data; therefore, the injury risk curves using German GIDAS data are applicable to Sweden. The regression models yielded the following results for unconditional injury risk curves: 10 % MAIS2+ at 25 km/h impact speed for frontal head-on crashes, 20 km/h for frontal car-to-object crashes, 55 km/h in far-side crashes, and 45 km/h in near-side crashes. A 10 % MAIS3+ risk was reached between 70 and 75 km/h for all crash types. Conditional injury risk curves gave substantially different results; the 10 % MAIS3+ risk in near-side crashes was 140 km/h, twice the unconditional value. For example, if a 10 % MAIS3+ risk was acceptable, treating remaining uncertainty conservatively, assuming compliance with speed limits and that Automated Emergency Braking takes 20 km/h of the travel speed before impact in longitudinal traffic, the safe speed limit for car occupants on most Swedish roads would be 80 km/h and 60 km/h in intersections.

Car occupants

Impact speed

GIDAS

Unconditional

Safety

Crash type

Författare

Nils Lübbe

Chalmers, Mekanik och maritima vetenskaper, Fordonssäkerhet

Autoliv AB

Hanna Jeppsson

Autoliv AB

Simon Sternlund

Trafikverket

Alberto Morando

Autoliv AB

Accident Analysis and Prevention

0001-4575 (ISSN)

Vol. 202 107586

Ämneskategorier

Transportteknik och logistik

Infrastrukturteknik

DOI

10.1016/j.aap.2024.107586

PubMed

38669899

Mer information

Senast uppdaterat

2024-05-08