The measurement and analysis of road travel activity -- exposure (to risk) -- is a fundamental requirement of both energy efficiency and safety research. One of the main objectives of road safety research is the development of methods for estimating road travel risks for various (groups of) entities under different travel conditions and temporal periods. The ability to measure and compare the level(s) of road travel risk associated with the various human-vehicle-road/infrastructure-environment-trip-temporal factors and their characteristics provides the necessary information required for identifying `high risk' road travel behaviour patterns. Using this knowledge of the road travel risks, in conjunction with the magnitude of the problems (i.e., incidents of accident/injury/fatality representation) and other available research information permits the prioritisation of the identified problem areas and issues requiring attention. Then the process of identifying new countermeasures or remedial measures for reducing the identified 'high risk' road travel behaviour and patterns can be pursued. This paper presents some ideas, concepts and methodological approaches for the design, development and implementation of a `standardised' risk analysis and evaluation system. A modelling framework along with the processes for conducting risk assessment/evaluation studies are discussed. Optimal methodologies are developed for the derivation of three types of road travel risk performance measure indicators - - `basic risks', `relative risks' and `relative risk odds-ratios' - - for estimating, monitoring, comparing, interpreting and evaluating the level(s) of safety prevailing on the road and highway systems at any given time. The methodologies include: statistical and mathematical methods and techniques for estimating and comparing the road travel risk estimators; `accuracy assessment' methodologies for measuring the statistical level(s) of accuracy associated with the various road travel risk estimators. Examples for each type of risk evaluation are provided. A computer software system (presently under development) for the implementation of the methodologies and procedures contained within the Risk Analysis and Evaluation System Model (RAESM) framework is described. The paper concludes with some thoughts on two critical issues that affect our ability to make progress towards understanding the road travel risk level(s) existing on the road and highway systems. The `missing links' -- a 'lack of relevant, accessible, timely, standardised exposure (to risk) data'- - that presently impede our capacity to implement a risk analysis and evaluation system, and the `serious consequences of not developing a comprehensive and continuous national exposure (to risk) data' -- that presently impede our capacity to implement a risk analysis and evaluation system, and the `serious consequences of not developing a comprehensive and comprehensive and continuous national exposure (to risk) data collection system and database' are discussed. (Author/publisher)
Samenvatting