The University of Tennessee, Knoxville


Maintenance of Drainage Features for Safety

by Dr. Airton G. Kohls (Source: FHWA - Office of Safety)

Have you ever experienced the situation of driving over standing water in a road? It is not a good feeling and it can result in serious consequences. FHWA provides a guide for local street and highway maintenance personnel, highlighting the importance of maintenance of drainage features for safety.

Clogged Drain

Recognizing drainage problems is the first step to efficiently address safety issues. Drainage problems like water ponding in wheel ruts, water standing in the roadway, water ponding in the edge of the roadway, deterioration of pavement edge and shoulder, etc. can directly cause or contribute to crashes. As an example, drainage features that fail to remove run-off because they are too small or are clogged and pond water on the roadway can cause hydroplaning or force drivers to leave their lane. It is important to identify these potentially hazardous situations as soon as possible. Some of these conditions may have been in existence for quite some time, while others may have recently developed as a result of a storm or change in weather conditions.

Drainage problem locations can be identified by citizen complaints, local police, crash data or field reviews. Potentially hazardous drainage features are best identified through field reviews. Drainage features should be inspected periodically! Here is a field inspection checklist - check for the following conditions:

Standing Water

Grated Inlet

Access points, such as road intersections, driveways, pedestrian and bicycle crossings are important areas where drainage features should be reviewed and, where appropriate, improvements made. At access points the grade of the highway and the access point have to meet. Consequently, the free flow of run-off is restricted and some drainage feature is usually built to move the water away. Drainage facilities, particularly those for driveways, may have been poorly constructed by developers or property owners and may be potential hazards. In the photo below, water is ponding because the outflow ditch has silted up. Grated inlets can be used to prevent water ponding at access points.

Remember, regular maintenance of drainage features can save lives!

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