Details

Autor(en) / Beteiligte

• Pei, Xin
• Wong, S.C.
• Sze, N.N.

Titel

The roles of exposure and speed in road safety analysis

Ist Teil von

• Accident analysis and prevention, 2012-09, Vol.48, p.464-471

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• ► GPS probes data was used to determine speed and time exposure. ► The correlations between speed and crash risk are opposing with respect to distance and time exposure. ► The correlation between speed and crash risk is negative when controlling for the effect of time exposure. Speed is a determining factor in road safety analysis. It is generally believed that an increase in speed harms road safety. However, it can also be argued that driving at high speed reduces the length of time exposure and thus the likelihood of a crash. It is therefore critical to clarify the roles that exposure and speed play in road safety analysis. This study evaluates the relationship between speed and crash risk with respect to distance and time exposure, using disaggregated crash and speed data collected from 112 road segments in Hong Kong. A joint probability model based on a full Bayesian method is applied simultaneously to model crash occurrence and crash severity. In addition, we consider the explanatory variables, including road design, weather conditions, and temporal distribution, in the proposed crash prediction model. The results indicate that average speed plays a significant role in crash risk, despite opposing correlations with respect to distance and time exposure; the correlation between speed and crash risk is positive when distance exposure is considered, but negative when time exposure is used. However, in both cases, speed is positively associated with the injury severity.