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Weather related intelligent speed adaptation

Funding Organisation: VTT, Technical Research Centre of Finland


The objectives of this study were:

  • To compare ways of supporting the driver when adverse road conditions are difficult to detect (black ice).
  • To develop and test methods of informing the driver of adverse conditions.

A sample of British and Finnish drivers drove the LADS in one of the following conditions:

  • No extra information.
  • Simulated Variable Message Signs (VMS) indicating areas of low road friction.
  • Intelligent Speed Adaptation (ISA), automatically slowing the car when in contact with areas of low road friction.
  • Various in-car devices to warn the driver of low road friction.

Results showed that the adaptation by the driver alone is not usually adequate to maintain safe driving in icy conditions, as drivers have difficulty in assessing the degree of road friction. Methods advising the driver of low road friction (VMS, in-car) were not sufficient to adapt their behaviour significantly. However, the weather-related ISA was able to support driver sufficiently to increase overall travel speeds, but improve safety in critical areas of low road friction.