Possible alternative exposure measures

Fuel consumption could be regarded as an alternative for vehicle kilometres. It is also sometimes used for the estimation of vehicle kilometres. One of the drawbacks of this exposure measure, compared to the actual vehicle kilometres of travel, is that short term fluctuations in road use may not be easily captured. Obviously, fuel is consumed some time after sale, which cannot be determined precisely. Accordingly, it is also difficult to determine where fuel is consumed. Therefore, fuel sales are probably best used at an aggregated level, possibly national and annual. However, when comparing countries additional parameters should be taken into account, such as fuel efficiency of motor vehicles, pricing differences etc.

Like fuel consumption, the number of vehicles in the vehicle fleet could be regarded as an alternative of vehicle kilometres. However, it is not recommended to be used as a replacement of vehicle kilometres, as it is possible that vehicles on average drive more kilometres over time. Nevertheless, comparing the number of accidents corrected for the number of vehicles is likely to be informative. Furthermore, vehicle information, mainly type, age and physical characteristics that are not likely to be easily available for vehicle kilometres may be available for the vehicle fleet. For private cars, the age of the owner may also be of interest. Influences of foreign vehicle fleets (e.g. from neighbouring countries) may have to be considered.