Emeli Adell

Test of HMI Alternatives for Driver Support to Keep Safe Speed and Safe Distance - A Simulator Study

This paper describes a driving simulator trial to evaluate driver reactions to a number of alternative information/ warning modes of a multi-modal system for the “safe speed and safe distance” concept. In 2006, eight Human Machine Interaction alternatives, consisting of a combination of visual, haptic and auditory modes were used alternatively to give information/warning to the driver on safe speed, safe distance and the prevailing speed limit. Thirty-four test drivers drove once without the SASPENCE system and twice with the system. The system did not affect the speed behaviour of the driver in either normal conditions or sharp curves. The average number of alarms was slightly larger when driving with the system. The haptic HMI alternative - the combination of force feedback in the accelerator pedal and vibration of the seat belt for speed warning and pulsation in the accelerator pedal for distance warning - gave the lowest proportion of time of being in an unsafe situation, and improved driver-reaction time most. This haptic alternative also resulted in the most positive driver ratings/experiences of the system. The visual alternatives used were positively rated by the drivers, but no clear differences between them could be found according to opinions. The auditory feedback was not appreciated by the drivers. All the drivers stated they would accept the SASPENCE system if the system was installed in their cars free of charge. The majority would accept a system that was both informative and advisory, while some of them also stated they would accept an intervening system. (Less)

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. (Less)