Lower emissions from existing cars: personalised advice based on emission maps

Pollutant emissions from the passenger car fleet in Europe can not only be reduced by the influx of clean new vehicles, but also by reducing the emission levels of existing vehicles. Since for a number of reasons the average fleet emissions do not decrease as fast as envisaged by policy makers, attempting to reduce the emissions from the present fleet can be an attractive and potentially powerful option, with direct effects. The exhaust and wear emission levels of an individual vehicle depend among other things on the euro standard, the precise engine and exhaust gas aftertreatment system, weight of the vehicle, brake and tyre composition, the state of maintenance, originality of the technical specs, and age of the vehicle. However, to which extent the potential emissions actually take place, is greatly influenced by driver behaviour, the use case of the vehicle and the local conditions, as emissions vary among different circumstances. To advise owners and drivers on reducing the emissions of their vehicle, all of the factors need to be taken into consideration. The heart of the present work is the standardisation of the information describing the relationship between vehicles in use and their emissions, on the basis of which the personal or fleet-emission reduction potential can be determined. Individual advice should be based on appropriate measurements, of that particular vehicle or a similar vehicle. Moreover, presenting such information should be transparent, so conclusion and limitations of the underlying data should be clear.