This chapter discusses methods for identifying high risk locations, and the ways that different sources of data can be analysed to assess the causes of this risk. The assessment of potential risks and identification (or ‘diagnosis’) of issues are the first steps of the risk assessment process introduced in Infrastructure Safety Management: Policies, Standards, Guidelines and Tools (Figure 10.1).
The traditional approach used in the identification of risk is the analysis of historical crash data. This approach is still very relevant, but in recent years there has been recognition that other sources of information should also be used in the risk assessment process. This broadened proactive approach is important in all countries, but particularly in LMICs where crash data may be of poor quality. Proactive approaches are being increasingly used in HICs to supplement historical crash data. Although this chapter is structured to present separate information on each approach, it is very important that both proactive and reactive approaches be used in the assessment of risk.
The focus of this manual is on the elimination of death and serious injuries, as these are the crash types that have the greatest societal impact. However, identification of high risk locations involving death and serious injury does not just involve analysis of fatal and serious injury crash data. Other sources of information can also be used to identify likely locations where serious injury or death may occur.
The following section provides brief information on project- and programme-level approaches to risk assessment, while Crash-based Identification (‘Reactive’ Approaches) discusses crash-based methods for identifying and assessing risk. Proactive Identification provides information on the proactive approaches, including impact assessment, road safety audit and road safety inspection Combining Crash Data and Road Data brings both the reactive and proactive approaches together to discuss an integrated approach to assessing risk.
Guidance documents on the assessment of risk are available, and should be adopted by all countries and embedded within core business. Training in the use of the following tools should be provided:
As a priority, assessment should be undertaken on high risk routes and corridors (see Belize case study in Box 10.1), utilising crash data were available (Crash-based Identification (‘Reactive’ Approaches)) as well as information on safety-related road elements (e.g. through safety audit and road assessment programmes – see Proactive Identification).