Why Potholes Are More Common on the Outer Edges of Roadways

Potholes are failing points on road surfaces, commonly found in areas where the roadway material, such as asphalt in flexible pavements and concrete in rigid pavements, becomes weakened due to fatigue. While potholes can occur anywhere on a roadway, they are notably more prevalent on the outer edges due to several contributing factors. In this article, we will explore these factors in depth and discuss maintenance solutions to minimize their occurrence.

Water Accumulation and Frozen Expansion

The outer edges of roads often have poor drainage, resulting in water accumulation. When water seeps into cracks in the pavement and freezes, it expands, leading to further cracking and eventual pothole formation. This process is a significant contributor to the higher incidence of potholes on the outer edges.

Increased Wear from Traffic

The outer edges of roads frequently experience increased wear due to vehicles drifting out of their lanes, particularly larger vehicles like trucks. This constant movement creates additional stress on the pavement, which can lead to greater deterioration over time. The outer edges can become more vulnerable to pothole formation due to this increased impact.

Lack of Maintenance

Another factor contributing to potholes on the outer edges is a lack of maintenance. Roadway edges might not receive the same level of upkeep as the center of the road, leading to more significant deterioration over time. Regular inspection and maintenance of these areas are crucial in preventing pothole formation.

Design Factors and Camber

Many road designs incorporate a crown or slope towards the center, assisting in drainage through weep holes. This design helps to discharge water to the adjoining drainage system, but it also has an unintended consequence: it forces more water to accumulate at the outer edges. This concentration of water can weaken the surface material, leading to distress and eventually, potholes.

To address the issue of water accumulation at the outer edges, one potential solution is to reduce the distance between the discharge holes in the curb. This can help to distribute the water more evenly, thereby reducing the concentration of water at the outer edges and decreasing the likelihood of pothole development.

Conclusion

In summary, potholes on the outer edges of roadways are a result of a combination of factors, including poor drainage, increased wear from traffic, lack of maintenance, and the design of the roadway camber. Addressing these issues through better maintenance practices and design solutions can help to reduce the frequency and severity of potholes in these areas.