Common methods for estimating the safety effects of road improvements

Abstract

There are major differences in traffic and safety records between Lithuania and Finland. However, safety tools exist that are useful to both countries. The main features of these tools are presented along with some results of comparisons between the countries. One common tool is for road safety ranking and analysis of the safety effects of road improvements. It is based on empirical Bayesian estimation of the current safety situation, and on worldwide information on safety impact coefficients, also known as Crash Modification Factors (CMF). Comparison of the Lithuanian and Finnish accident models suggests that the main features affecting safety are similar even in different kinds of countries. Another common tool is for accident analysis. It uses the data commonly collected from accidents as follows: (i) accident events, together with their location-related data, (ii) traffic units involved, such as vehicles and pedestrians, and (iii) persons involved, including those in/on vehicles or on foot. The tool is used to study the features of accidents on certain roads and in certain areas or conditions, in order to estimate the possibilities for road safety improvements.