Development of crash reduction factors: methods, problems, and research needs.

Author(s)
Shen, J. & Gan, A.
Year
Abstract

Crash reduction factors (CRFs) are used in highway safety studies to predict safety benefits due to reduced numbers of crashes. NCHRP Report 162 identified the need for the development of a national comprehensive set of CRFs for each state to evaluate safety improvements. However, this need has not been met. As a result, many states have developed their own CRFs or have adopted CRFs from other states. A synthesis of the CRF development methods, the associated problems, and the research needs are provided. The emphasis is placed on the before-and-after study method because it has been, and still is, the method of choice for CRF development. Three before-and-after study methods were introduced and reviewed: (a) the simple before-and-after method, (b) the before-and-after study with comparison group method, and (c) the before-and-after study with the empirical Bayes method. The problems associated with the simple before-and-after studies, including regression to the mean, crash migration, maturation, and external causal factor, are discussed. Several research needs related to crash migration and general CRF development are also identified. The information presented in the synthesis will be useful to states that plan to develop or update their CRFs.

Request publication

2 + 9 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.

Publication

Library number
C 32679 (In: C 32674 S [electronic version only]) /80 / ITRD E828727
Source

In: Statistical methods and modeling and safety data, analysis, and evaluation : safety and human performance, Transportation Research Record TRR No. 1840, p. 50-56 (2 Fig., 32 Ref.)

Our collection

This publication is one of our other publications, and part of our extensive collection of road safety literature, that also includes the SWOV publications.