Of growing concern to Dutch and European policy-makers is the fast-rising number of vans and light trucks on the roads and the growing number of casualties and emissions due to these vehicles. As fleet operators face relatively high costs with this type of vehicle (fuel, maintenance, accidents), engine speed limiters may be one way of helping drivers adopt a more fuel-efficient and safer driving style.
At the request of the Netherlands Agency for Energy and the Environment, Novem, a large-scale practical trial with speed limiters was organised, in which sixteen companies operating a total of 177 vans and 30 trucks in the 3.5 - 12 tonne category participated for a period of one year. The impacts of speed limiters on fuel consumption, vehicle maintenance, accident damages and speeding tickets were monitored. The experiences of drivers and fleet operators were also assessed.
The following main results and conclusions emerged:
- On average, 5% fuel savings were achieved with the speed limiters, a figure in agreement with the results of an earlier, theoretical study by CE (“Speed limiters on vans and light trucks”, 1998) and the outcome of practical trials by Carglass, in which fuel savings were also recorded for vehicles in a control group; this is probably due to an overall ‘culture shock’ at the firms in question, prompting drivers of these vehicles to drive more conscientiously and efficiently, too.
- Following installation of engine speed limiters, there was a clear decline in the number of speeding fines for all participants, including the control group.
- From these trials no conclusions can be drawn on the influence of speed limiters on accident costs, as there were too few instances of such damages in the one-year trial period. In the long term, though, fleet operators themselves expect to earn in this respect, too.
Based on these results, purely in terms of fuel savings the break-even point for fleet operators of a retrofitted speed limiter (costing about 700 euro) is about 170,000 km. For an ex-works programmed maximum engine speed (costing about 0-100 euro) this is about 25,000 km. If the anticipated benefits vis-à-vis damages and maintenance are also included, these figures will be lower.
Besides the above findings, the report also provides leverage for policy-makers as well as suggestions as to how operators can successfully implement engine speed limiters.