The New South Wales intelligent speed adaptation trial: further results

This paper presents further results of the NSW Intelligent Speed Adaptation (ISA) Trial. The NSW Centre for Road Safety conducted the largest trial of this type in Australia in 2009 to 2010. Over 110 light vehicles from private and company fleets were fitted with an advisory ISA device and a speed data recorder. Each vehicle remotely communicated with a centralised database to ensure it received up-to-date speed zone information. Over seven million vehicle speed records were collected during the trial, which were analysed to measure changes in speed compliance. The advisory ISA system reduced speeding in 89 per cent of trial vehicles. The median probability of speeding was also reduced by almost 30 per cent when advisory ISA was active. When the advisory ISA system was removed 85 per cent of vehicles increased the proportion of their trip time that they travelled in excess of the legal speed limit. Results of the trial demonstrate that advisory ISA technology has the potential to realise substantial road safety benefits by increasing drivers' compliance with speed limits.