TNS NIPO has conducted a motivation survey in August 2008, in which they asked car drivers whether they were aware of the tips of the Dutch Ecodriven Program (HNR) and whether they actually drove according to these tips. The results show that 94% of the respondents claim to drive according to one or more of the HNR-tips. The aim of the current TNO research commissioned by SenterNovem is to investigate the actual driving behaviour of two groups of drivers. These groups are defined based on the results of the motivation survey of TNS NIPO. The first group is described as appliers of the HNR-tips, the other group as non-appliers. The current study compares the actual driving behaviour of these two groups of drivers. The study consisted of a driving test with an instrumented vehicle (a VW Passat TSI with a 2.0 liter gasoline engine with a manual gear box). Appliers and non-appliers drove a fixed route composed of roads with different maximum speeds, intersections, roundabouts, both inside and outside the built up area. The route was specifically selected for good opportunities to apply the HNR-tips. During the test drives, a number of data were recorded from the CANBUS of the vehicle (a.o. speed, following distance, RPM, gear shifts and fuel consumption). Also an assessment was made of the driving performance on behalf of energy efficiency and safety by a qualified driving instructor. The analyses show that appliers cannot be distinguished based on their driving behaviour with respect to applying the HNR-tips. It is concluded that the subjective experience of the appliers that they drive according to the HNR-tips does not correspond with their actual behaviour. After this finding, TNO has made two new post hoc categories of drivers, based on their actual fuel consumption because this is one of the main issues of HNR. These new groups were called ‘fuel efficient’ and ‘non fuel efficient’ drivers. This way it was possible to analyse the relation between driving according to the HNR-tips and fuel efficient driving. The results of this analysis show that fuel efficient and non fuel efficient drivers can be clearly distinguished by the way they apply tip 1 (change gears) and 3 (drive 80 in fifth gear). They can also be distinguished by the assessment of the driving instructor. It is concluded that there is a group of drivers who actually applies the HNR-tips and drive in a fuel efficient way. However, this group can not be discerned based on their answers on the motivation survey. It is only possible to discern this group by actual fuel consumption or by having a qualified driving instructor make an assessment of the driving behaviour. (Author/publisher)
Samenvatting