Intelligent Speed Adaptation

WSP Opus investigated whether intelligent speed adaptation systems could help to lower the crash rate in New Zealand. Around 70% of rural crashes on bends happen on curves that can only be safely negotiated at speeds considerably lower than the speed limit.

New Zealand uses recommended speed signage to signal drivers that they are approaching a significant curve to try to reduce this crash rate, however compliance with the recommended speeds is low. 

NZTA wanted to examine the benefits of using GPS technology to increase driver compliance with the recommended speed. Intelligent Speed Adaptation (ISA) systems have been widely used and evaluated overseas and shown to reduce speeding.

These systems use GPS information to inform the driver of their speed relative to the speed limit, with feedback to the driver varying from visual and audio response to limiting vehicle speed. As significant investment would be needed to implement an ISA system in New Zealand, proof of its benefits and an evaluation of the costs were needed.

WSP Opus was part of a project funded by NZTA that examined the use of ISA systems in New Zealand, along with collaborators from MWH and the University of Leeds. The research focused on a version of ISA that provides recommended speeds for specific curves, as well as speed limit information. We wanted to find out how drivers responded to having the technology in their cars and what difference it made to how they drove.

Our team focussed mainly on user acceptance of the technology, the effect on driver behaviour, and any legal barriers to introducing an ISA system in New Zealand (such as legal challenges to Police speed measurement and enforcement). Focus groups were used to determine what people want from ISA systems, how they would like them to be designed, and what incentives might encourage their use.

The research provided evidence that ISA technology could have a positive impact on driver behaviour and in reducing crashes.