Emission control options for power two wheelers in Europe

This paper quantifies the emission contribution of motorcycles and mopeds in Europe, in the period 1999–2012. Projections show that these vehicles will emit more than 7% and 20% of total road transport CO and HC, respectively, by the year 2012, if no additional regulatory measures are taken. In contrast, they will continue to be negligible NOx (0.7%) and CO2 (<1%) emitters, while their particulate matter (PM) emission contribution is expected to decline to below 1% in the future. The relative importance of their emissions, however, increases in urban environments, especially in southern European countries, which host large fleets of small two wheelers. Hence, further regulatory measures are being considered which include durability requirements for the emission controls, in-use compliance and roadworthiness procedures, on-board diagnostics, control of evaporation emissions, PM specific measures and new steps for emission standards. The study quantifies the environmental benefits and the costs associated with each measure, and calculates cost-effectiveness figures which may be used to evaluate each policy option. Results show that for the reduction of HC emissions, both evaporation control and roadworthiness tests are cost-effective while a further tightening of the emission standards for mopeds will bring the largest benefit. Additionally, on-board diagnosis for motorcycles is found to be an expensive measure with questionable effectiveness, while the replacement of mineral with synthetic lubricants would bring clear benefits with respect to PM of 2-stroke engines.