Common terms explained in plain language

Tire Marks

  

If you ask the average person what to call a set of tire marks on the roadway, they would probably respond "skids". In reality, they may be something else altogether. We generally classify tire marks as one of three types: skid, scuff or print.

A skid is caused by a tire that is locked and sliding. A skid mark is caused by the heat generated by that tire action. Contrary to popular belief, a skid mark is not a rubber smear on the road. When a vehicle is braking and the tires lock up, a certain amount of heat is generated. As the heat builds, the oils from the road composition rise to the surface and create the visible mark. The tread grooves of the tire will be quite visible. This is why we rarely see good skid marks on concrete. Of course, a certain amount of the smear is rubber, but very little.

A scuff is caused by a tire that is rolling and sliding. Yaw marks, which will be discussed in greater depth later, are scuff marks. The result of the heat buildup between the sliding tire and the road surface creates a distinct mark. It will be black as in a skid. But striations, or diagonal lines will be present as opposed to the clear tread grooves we see in a skid. These striations are actually the tread pattern as the tire is rolling while it slides. This causes it to leave this unique pattern. 

A tire print is caused by a rolling tire that has gone through some liquid or semi-liquid material and leaves a track as it goes. Picture a car driving through a water puddle on an otherwise dry road. As it leaves the puddle, the tire will leave a print until the water dries.

-

-

-

-

-

-.