The Netherlands intends to introduce a road pricing scheme and the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) asked CE Delft to assess the impact on particle emissions of varying the kilometre charge according to whether or not vehicles are fitted with a particle filter. The scheme was conceptualised as a penalty/discount system, with diesel cars lacking an ex-works particle filter subject to a penalty of 2.5 Euro cents on top of the standard kilometre tariff and other vehicles being eligible for a discount. The level of this discount was designed such that the kilometre charge remains cost-neutral for motorists.
The effects of particle-filter differentiation of the kilometre charge were estimated using the elasticities reported in the scientific literature. This yielded a projected reduction in PM10 emissions of between 0.01 and 0.06 kt in 2020, or 1 to 7% of the total particulate emissions of passenger cars. There would be a similar percentage reduction in PM2.5 emissions.
The focus in this study was on particulate emission cuts in the year 2020, rather than in the intervening years. The environmental impact in those intervening years is anticipated to be even greater, given that during this period the fleet will have an even greater proportion of diesel vehicles without a filter. After 2020 the impact of particle-filter differentiation of the kilometre change will decrease. Further study could chart the course of the effectiveness of the measure over time.