DRIVERS' EVALUATIONS OF THE ACTIVE ACCELERATOR PEDAL IN A REAL-LIFE TRIAL

In a large-scale field trial, conducted between 2000 and 2001, the test drivers used the Active Accelerator Pedal for between 6 and 12 months in their regular cars. The drivers ' evaluations, elicited by questionnaires after one month of usage and at the end of the trial, were analysed with ANOVA (repeated-measure) and compared to the objectively measured effects in the same trial. The drivers found the system to be effective in decreasing their speed and believed their risk of being fined for speeding decreased drastically. On the other hand, their workload increased and their emotional state deteriorated. They reported an increased feeling of obstructing other drivers and reduced driving enjoyment. Between-subject effects showed a different way of using the system depending on age; younger drivers used the supporting function of the system more, while older drivers found the counter force more of a command to lower their speed. Time effects showed the importance of long-term evaluations and the interaction effects demonstrated how development of driver responses over time depend on driver type and initial attitude. Comparing driver subjective experiences and objectively measured effects, discrepancies were found in the magnitude of speed changes and car-following distances. The delegation of responsibility coincided well with the objectively measured effects.