Perceptual countermeasures (sometimes call perceptive countermeasures) are any alterations to the road environment to change a road user’s perception of the environment with the aim to alter their behaviour. Common perceptual countermeasures include transverse lines (lines across the lane), altering guidepost spacing, 3D line marking and lane narrowing.
There have been many studies of perceptual countermeasures over the years, all of which generally show a small improvement in safety. They’re certainly not going to get us to zero, but they do provide some road safety benefit when used in the right context.
One road user that may see potential safety gain are motorcyclists. This is because appropriate perceptual countermeasures can influence riding speed, but also lane position.
Safe System Solutions Pty Ltd, in partnership with the Centre for Automotive Safety Research (CASR), is currently undertaking research and trials for Austroads perceptual countermeasures for motorcycle safety (SAG6222).