Intelligent Speed Adaptation for involuntary drivers: Final results

The Danish Intelligent Speed Adaptation (ISA) trial ISA C included 26 commercial cars and 51 drivers a number of whom were involuntary. After a baseline period, ISA was activated for one year. The drivers should identify themselves with a personal key ID before driving. As well as being informative and warning, the ISA had an incentive in the form of rewards for speeding avoidance and social control - the latter, however, did not work sufficiently. When a key ID was used, the proportion of speeding was low while driving with ISA. Without key ID there was virtually no change in driving behaviour regardless of ISA. Also, a statistical model showed that drivers sensitive to ISA sped significantly less in baseline than insensitive dri- vers. Moreover, on the basis of questionnaires it was found that drivers could be categorised as either green drivers (not positive to speeding) or red (more positive to speeding). A high correlation between the use of key ID, sensitivity to ISA, and the driver’s colour was found: green drivers would use the key ID while red virtually never did. Hence ISA, as used in this trial, has virtually no effect on the driving behaviour of involuntary drivers