Why is there a need to provide highway drainage ?

• To prevent ponding & flooding
• To optimise skidding resistance and prevent aquaplaning
• To stop water getting into the foundations of the road

Skid Resistance & Aquaplaning
A vehicle skids when there is a loss of friction between the vehicle's tyres and the road surface. Since all the materials used in road surfaces provide a high level of friction, skidding rarely happens in dry, normal conditions. When it does happen it is normally the result of driver error.

When a road becomes wet, the contact between tyre and road lessens and increases the risk of skidding. Road surfaces and vehicle tyres are designed to minimize this risk.  Aquaplaning occurs when a film of water gives rise to little or no contact between the vehicle tyres and the road surface.