Road agencies typically allocate funding to improve high risk locations, whether based on crash history or on the potential risk. This funding may take the form of dedicated funding for high risk locations and/or be embedded in other operating budgets (for example, major projects or asset management). Most actions undertaken by a road agency have a safety impact, whether they are initiated for safety reasons or not. If consideration of safety is included in all decision-making, safety risk can be reduced, often at little or no additional cost. The assessment of risk needs to occur at the programme and project level, and the advice provided in this chapter is relevant to both.
Assessment of risk should be undertaken for the entire road network for which the road agency is responsible. Such an approach would require a network-wide assessment of risks and issues. The outcomes of such an approach would identify key crash types, trends, geographic regions or areas, deficiency types, etc., with the outcomes of this assessment informing programmes of work.
It is often the case that a small percentage of roads account for a large percentage of deaths and serious injuries. At the programme-level, the task is to identify such routes and address these. For those countries with limited resources or that lack adequate data across the whole network, such locations are the most important to assess. These locations can form the basis of a corridor demonstration project. The content from this and the following chapters can be used as a guide to the assessment of risk across networks or along corridors. The examples below provide information on the corridor approach in Belize (Box 10.1) and in New South Wales, Australia (Box 10.2)
The solution: A multi-sector approach was taken to assessing road safety in Belize. Part of that project involved infrastructure improvements for a demonstration corridor. The initial process for this infrastructure improvement component involved:
Specific investment options were recommended to the project stakeholders, with the ultimate decision on an appropriate investment level determined by the road authority staff in Belize. Improvements on an 80 km demonstration corridor between Belize City and Belmopan were agreed. Safety improvements included:
Road fatalities and injuries were modelled for the demonstration corridor, with and without the recommended improvements. An economic evaluation compared the incremental costs and benefits of these two alternatives. The results of the incremental analysis indicated that for the level of investment proposed, 470 fatalities and serious injuries could be avoided over the 20-year analysis period. This is equivalent to a reduction of 20% in the number of injuries and fatalities over a 20year period.
Using very conservative crash cost values, the estimated net present value (NPV) of the project is US$6.1m, and the economic rate of return (ERR) is 28.8%. The ERR is well above the Caribbean Development Bank’s cut-off rate of 12.0%, which highlights the significant economic benefits that can be had from road safety investments.
The economic analysis focused on the quantifiable costs and benefits related to the safety infrastructure improvements on the demonstration corridor, as these can be estimated with greater reliability and robustness. However, the institutional strengthening and capacity building components are also expected to have a significant impact on road safety throughout the country. Tangible benefits are also expected from proposed road education, awareness and communication activities.
The outcome: This project is still being evaluated, but early indications are positive.
Source: Belize Ministry of Public Works and Caribbean Development Bank
The solution: New South Wales developed road safety reviews of major roads as a dedicated corridor approach to the analysis and selection of engineering works (and some behaviour change programmes) to improve road safety. Road safety reviews are different from engineering audits and blackspot programmes. They focus on a single corridor, analysis of fatal crashes, and a physical review of the entire highway by a multidisciplinary road safety team (that includes expertise in engineering, road design, behavioural science/psychology, statistics, and policing). The review process does not focus on where the road does not meet standards, but rather it focuses on analysis of fatal crash locations. The review team considers the highway as a whole and addresses the question of how to avoid injury occurring, rather than how to avoid the crash occurring. Further details of this approach can be found in de Roos et al. (2008).
The outcomes: The road safety gains achieved have been strong, as indicated in the figure below. On the Pacific Highway (of over 600 km), comparing crashes in the years before to the years after the selected works showed a 45% reduction in deaths and strong reductions in injuries. The same process on the Princes Highway (over 400 km) resulted in an 83% reduction in deaths on the highway and strong reductions in injuries. These reviews yielded an average benefit cost ratio of over 12:1 for the works, well above the benefit cost ratios achieved with traditional blackspot programmes or engineering audits in the state.
At a project level, the steps outlined in this chapter are equally relevant. They highlight how to identify risk at more specific locations (e.g. intersections, routes or areas) and diagnose risk at these locations. Crash-based (reactive) and more proactive approaches are relevant to both programme- and project-level approaches. In each case (whether programme or project level) the same steps are involved in assessing risks and identifying casual issues.