An Extension of the Induced Exposure Method of Estimating Driver Risk

Abstract

An important problem in road safety is to estimate the rate of involvement of drivers in accidents per unit of exposure, or road usage. Typically, good data on numbers of drivers involved are available for the numerator of this ratio, but data on road usage for the denominator are often not available. To circumvent this difficulty, techniques of induced exposure were developed in the 1960s, to derive estimates of rates of driver involvement solely from data on numbers of drivers. None of the existing variants of the induced exposure technique seems entirely satisfactory, however. This paper derives a new version of the induced exposure approach and illustrates its application to accident data for Scotland over the period 1986-90.

Nighttime driving, passenger transport, and injury crash rates of young drivers

“…A thorough summary of the history and theory of the method is found in Cuthbert, 13 thus we give only a brief description.…”

The efficiency of using non-culpable crash-claim involvements from insurance data as a means of estimating travel exposure for road user sub-groups

“…However, definitions of responsibility that lie at the heart of the induced exposure concept originally conceived by Thorpe and Carr continued to be questioned as problematic, and alternative models were derived (e.g. Cuthbert, 1994) that built on Koornstra's 1973 work. Cuthbert posited that crash involvements could be described on the basis of two components -a driver-type factor and another factor based on random sampling from the crash population.…”

“…On the other hand, Cuthbert's (1994) methodology has the advantage that it does not directly involve culpability assessment. However, it does require extensive information on environmental components of crash involvement that may not always be readily available for a broad population of crashes.…”

“…In spite of deeming that their data appeared to confirm a major quasi-induced exposure assumption (namely that the non-responsible proportions were similar for different state-oflicensure groups) they concluded that quasi-induced exposure had limitations that made it unsuitable for estimating the numbers of unlicensed drivers on California roads. Cuthbert's (1994) formulation for extending the induced exposure concept was utilized by Redondo-Calderon et al (2001) and expanded by Li and Kim (2000) using a log-linear model for paired preferences in assessing crash risk for driver age/gender combinations. Both studies used data that it was claimed distinguished reliably between high-and low-risk driver/crash characteristic groupings, and both produced results that supported the applicability of the induced exposure concept where comparisons to travel survey data or expectations with respect to conventional exposure information were considered.…”

Estimating Driver Crash Risks Based on the Extended Bradley–Terry Model: An Induced Exposure Method

“…Although these methods have not been widely used because of their numerous assumptions and complex algebraic derivations, interest in using only crash data to construct a relative index of crash risk has renewed in recent years (Janke, 1991;Pendleton, 1996). Cuthbert (1994) developed a log-linear model for crash risk based on this idea.…”