This guide was prepared to help local road agency maintenance workers understand the importance of maintaining and upgrading drainage features on their road system. Storm water that stands or ponds on the road surface and shoulders can contribute to crashes. It can cause hydroplaning under water conditions and skidding under icing conditions. Water run-off can deteriorate the shoulder, sideslopes, and reduce the effectiveness of safety hardware (guardrails, sign posts, etc.) This guide identifies typical drainage problems and suggests corrective measures to improve safety.