Safe for the environment?
A model for quantifying environmental impacts in cost-benefit analysis of traffic safety measures
The government’s National Traffic and Transport Plan cites a long list of measures for further improving road safety in the Netherlands. To aid policy-makers in their choice, the Traffic Safety Research Foundation (SWOV) undertook to have these policy measures, and several others, subjected to a social cost-benefit analysis. SWOV asked CE to develop a suitable methodology for this purpose, in particular to quantify and assign a monetary value to the environmental effects of the measures.
This report describes the methodology developed, which can be used to assess how a given policy measure affects the environmental impact of cars, vans, trucks, motorcycles and mopeds, and more specifically emissions of CO2 (climate), NOx and PM10 (air pollution) and traffic noise. The method assesses these impacts up to year 2030.
The method assesses the change in the number of vehicle-kilometres driven by each vehicle category on each of the types of road identified in the government’s ‘Sustainably Safe’ policy document. Each road type has a different speed limit and thus a different speed of traffic flow. In addition, three types of ‘driving style’ were distinguished for each road type.
To quantify the environmental impacts of each combination of road type and driving style the methodology employs a basic set of emission factors (emissions per kilometre) for each type of vehicle, reflecting variation in emissions according to vehicle speed and driving style. The emission factors are predicted for future years up to the year 2030.
Once the environmental impacts have been quantified, they are monetarily valued using ‘shadow prices’, yielding a figure for total annual environmental costs or benefits. These shadow prices, based on several international stud-ies, are derived from the damage costs or prevention costs of the impact in question, i.e. the cost of the resultant damage to society or the price society is prepared to pay to avoid the impact. In the case of noise, valuation is based on changes in property value (including dwellings) due to noise nuisance.