Road vehicle emissions reduce air quality and contribute to climate change. To tackle these impacts progressively tighter emission standards have been introduced at the European level since the early ’90s, and a range of new engine and transmission technologies, particle filters and fuels developed by industry. With all these developments, however, it is not universally clear what the environmental benefits of a particular technology are at what additional cost such benefits come. At the same time, many vehicle owners and fleet operators would like to be more pro-active in improving the environmental performance of their vehicles. Against this background CE developed the Environment and Efficiency Scan (EES) software package for NOVEM, the Netherlands Agency for Energy and the Environment. The package can be used for assessing current fleet performance and comparing the costs and (environmental) benefits of alternative investment scenarios. Thus, for example, the additional costs and environmental returns of using LPG or natural gas as a light-goods vehicle fuel can be computed, or the CO2 emissions reduction attainable by operating state-of-the-art (direct-injection) rather than conventional (indirect-injection) petrol vehicles and the returns on initial purchase accruing through reduced fuel costs. The Environment and Efficiency Scan is designed primarily for analysing municipal vehicle fleets comprising ‘standard’ as well as other vehicles (e.g. garbage and street-cleaning units), but it will also be useful to companies operating extensive fleets of lease vehicles. With its expertise, CE can customise the EES software to provide dedicated vehicle fleet advice, as it has done for eight of Amsterdam’s municipal districts, the city’s Municipal Port Authority and the local authorities of Zoetermeer and Zaanstad. The software was updated at the end of 2001 to allow investment scenarios to be run through to introduction of the Euro-4 emission standards in 2005.