Cost-Benefit Analysis
Cost-Benefit Analysis (CBA) for road safety interventions
Uncovering the ROI of road safety
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To ensure road safety interventions are both effective and sustainable, the Sustainable Development Goals (SDGs) recommend evaluating their economic, environmental, and social impacts — commonly referred to as the "triple bottom line." However, in practice, economic considerations often dominate these assessments. Therefore, it is advisable to conduct a comprehensive Cost-Benefit Analysis (CBA) when implementing road safety measures.
The TRANS-SAFE consortium has adopted a method developed by the University of Cape Town, which was applied in the Western Cape Government's (WCG) Road Safety Implementation Strategy. This method offers a structured approach to selecting and analysing road safety interventions.
The first step in the process is to compile a shortlist of the most viable and promising road safety measures for the study area. This can be achieved either through expert discussions, where accident hotspots are identified, or by conducting a GIS-based hotspot analysis if road crash coordinates are available. Each measure needs then to be adapted into a scenario, detailing the scale of its implementation in both geographical terms and in terms of its potential to reduce fatalities and injuries.
In consultation with the WCG, a 20-year timeframe was chosen for the (CBA). Over this period, a detailed profile of both costs (covering initial capital outlay and ongoing operational expenses to maintain effectiveness) and benefits, specifically the reduction in injuries and fatalities, is required. In the South African context, the Road Traffic Management Corporation publishes the costs of crashes on an annual basis, essential for these calculations.
The cost of crashes from South Africa's Road Traffic Management Corporation:
It is an important first best practice step to establish country-specific cost of crashes!
Cape Town, South Africa
CASE STUDY
Stafford Street and 1st Avenue
The intersection between Stafford Street and 1st Avenue (image 1) was the site of a small intervention with big ramifications.
The site saw the implementation of a speed hump and mirror. The calculated cost-benefit ratio after 20 years is estimated to be over 1200 South African Rand (€60).
1200 Rand
Every rand invested generates a benefit of R1200 (€60) in the long term.
CASE STUDY
2121 Rand
Every rand invested generates a benefit of R2121 (€107) in the long term.
Hannes Louw Drive
A 40-metre kerb will be installed on Hannes Louw Drive, along with all necessary infrastructure such as signage. The expected lifespan of the kerb is between 40 and 100 years. Given this, only a one-off installation cost and minimal annual maintenance to repair damage is assumed.
The cost-benefit analysis shows that the investment breaks even in just over two years. In the long term, after 20 years, it is estimated that every rand invested will generate a return of 2121 Rand (€107).
The Safe Systems Approach
The assessment of affordable road safety interventions, through Cost-Benefit Analysis, has been used to calculate the impact of road infrastructure improvements. Some of these improvements are designed to reduce vehicle speeds, while others focus on enhancing post-crash care options.
