can enforced behaviour change attitudes: exploring the influence of intelligent speed adaptation

the theory of planned behaviour model (ajzen, 1985) was used to determine whether long-term experience with intelligent speed adaption (isa) prompts a change in speed related cognitions. the study examines data collected as part of a project examining driver behaviour with an intervening but overridable isa system. data was collected in four six-month field trials. the trials followed an a-b-a design (28 days driving with no isa, 112 days driving with isa, 28 days driving without isa) to monitor changes in speeding behaviour as a result of the isa system and any carry-over effect of the system. findings suggested that following experience with the system, drivers’ intention to speed significantly weakened, beyond the removal of isa support. drivers were also less likely to believe that exceeding the speed would ‘get them to their destination more quickly’ and less likely to believe that ‘being in a hurry’ would facilitate speeding. however, the positive change in intentions and beliefs failed to translate into behaviour. experience with the isa system significantly reduced the percentage of distance travelled whilst exceeding the speed limit but this effect was not evident when the isa support was removed.