  This study analyses the actual effect of a representative low-emission zone
(LEZ) in terms of shifting vehicle registrations towards alternative fuel
technologies and its effectiveness for reducing vehicle fleet CO2 emissions.
Vehicle registration data is combined with real life fuel consumption values on
individual vehicle model level, and the impact of the LEZ is then determined
via an econometric approach. The increase in alternative fuel vehicles (AFV)
registration shares due to the LEZ is found to be significant but fosters
rather fossil fuel powered AFV and plug-in hybrid electric vehicles than zero
emission vehicles. This is reflected in the average CO2 emissions of newly
registered vehicles, which do not decrease significantly. In consequence, while
the LEZ is an effective measure for stimulating the shift towards low emission
vehicles, the support of non-electric AFV as low emission vehicles jeopardizes
its effectiveness for decarbonizing the vehicle fleet.
