What causes tyre marks?

What causes those distinctive black tyre marks on the road?

If you’ve ever watched a racecar skid around a track then tyre marks on the road are probably a familiar sight to you.

The distinctive blackmarks can often be seen left behind on asphalt roads after an accident where the driver has had to brake suddenly.

It might look like pieces of rubber from the tyre have been scraped across the road, but it’s actually the asphalt that has been damaged from the friction. The friction that creates these tyre marks are caused by sudden braking or dramatic accelerating and are created as bituminous oils in the road to melt and rise to the surface.

Skid marks are important evidence when there has been an accident involving a vehicle, and detectives can determine a lot about the speed, direction and force exerted from the marks left on the road. You can do a bit of your own investigation too – it’s easy to tell if the marks were caused by a car with an automatic braking system because the lines will be lighter due to the friction-reducing release stop mechanism.

This article was originally published in How It Works issue 113, written by Charlie Evans

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