road grooves: why do they run the long way instead of across or diagonally to drain water?

Question

road grooves: why do they run the long way instead of across or diagonally to drain water?

In: Engineering

Answer 1

This method provides a smooth constant surface for tires to contact, but simultaneously provides channels for water to enter to keep it from being between the contact patch of the tire and the cement. It’s pretty much taking the idea of why tires have such grooves, and applying it also to the cement. If tires only used diagonal or across grooves to do what they do, it wouldn’t provide for a very smooth ride, so they too have some straight grooving.