What element must be considered for proper highway drainage?

For proper highway drainage, it is essential to consider water flow. Effective drainage systems are designed to manage the movement of water away from the roadway to prevent pooling, flooding, or erosion that can undermine the road structure. Understanding how water flows in a particular area helps engineers and planners create effective drainage solutions, ensuring that rainwater and runoff are efficiently diverted away from the pavement. This is crucial to maintaining road safety and longevity, as poor drainage can lead to water damage, increased maintenance costs, and hazardous driving conditions.

Factors such as traffic patterns, while important for overall road design, do not directly impact drainage efficiency. Similarly, uniform pavement thickness pertains to structural stability rather than drainage. Road signage, while vital for guiding drivers, is unrelated to how water flows and is managed on highways.