title: Methodological guidelines for developing accident modification functions.
abstract: This paper proposes methodological guidelines for developing accident modification functions. An accident modification function is a mathematical function describing systematic variation in the effects of road safety measures. The paper describes ten guidelines. An example is given of how to use the guidelines. The importance of exploratory analysis and an iterative approach in developing accident modification functions is stressed. The example shows that strict compliance with all the guidelines may be difficult, but represents a level of stringency that should be strived for. Currently the main limitations in developing accident modification functions are the small number of good evaluation studies and the often huge variation in estimates of effect. It is therefore still not possible to develop accident modification functions for very many road safety measures.
authors.affiliation: Institute of Transport Economics, Gaustadalleen 21, NO-0349 Oslo, Norway; Department of Civil Engineering, Aalborg University, Sofiendalsvej 11, DK-9210 Aalborg SV, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Elvik
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000706:statistics & numerical data; D017408:Guidelines as Topic; D006801:Humans; D008962:Models, Theoretical; D012449:Safety
keywords: Accident modification function; Evaluation studies; Guidelines; Methods; Road safety