On-road evaluation of Intelligent Speed Adaptation, following distance warning and seatbelt reminder systems: Final results of the TAC SafeCar Project

  • Published: Monash University Accident Research Centre - Report #253, 2006
  • Authors: M.A. Regan, T.J. Triggs, K.L. Young, N. Tomasevic, E. Mitsopoulos, K. Stephan, and C.Tingvall
  • Date Added: 08 Feb 2013
  • Last Update: 08 Feb 2013
  • Format: pdf


To evaluate the technical operation of a number of ITS technologies with high estimated safety potential; to assess the acceptability to drivers of these technologies; and to evaluate, in an on-road setting, the impact of these technologies, alone and in combination, on driver performance and safety.

Methodology: Real world trial (Field Operation Test) in Victoria, Australia. There were 23 ‘system’ driver and eight control drivers. Each of the system drivers experienced four technologies: Advisory ISA, Following Distance Warning, Seatbelt Reminder and Reverse Collision Warning. The control drivers had only seatbelt reminder and reverse warning.

Key Findings:

  • The ISA system had a positive effect in promoting safer driving.It reduced mean, maximum and 85th percentile speeds, and reduced speed variability in most speed zones. 85th percentile speed went down by 3.6 km/h on 50 km/h roads and by 3.4 km/h on 100 km/h roads.

  • ISA also reduced the percentage of time drivers spent travelling above the speed limit, and did not increase travel times. The percentage of time at 5 km/h or more above the speed limit was reduced by up to 70 per cent.

  • The behaviour in the after period (with no ISA) was similar to that in the before period.

  • The ISA system was generally rated as being useful, effective and socially acceptable.Based on the logged speed data, the ISA system was predicted to reduce the incidence of fatal RTIs by up to 8 per cent and serious injury RTIs by up to 6 per cent.


Intelligent Speed Adaptation


Only the findings for the Advisory ISA are highlighted here.