Your View: Explaining the science of road repaving

Your View: Explaining the science of road repaving

By Yon Lambert Director, city department of transportation and environmental services (File photo)

To the editor:
A recent letter to the editor noted the condition of South Pitt Street and several recent temporary repairs (“Band-Aid fixes have just made Pitt Street worse,” January 19). We appreciate the writer’s concerns and this opportunity to explain the science of road paving and how it relates to other roadway improvements for people who walk or bike.

Over the last four years, city council has increased funding for road paving by more than 250 percent, dramatically increasing the number of lane miles resurfaced. Last year alone, the city resurfaced 66 of our 560 lane miles of roads — the largest effort in more than a decade.

In addition, the city conducts a citywide inspection every three years to determine each street’s pavement condition index. This rating grades asphalt condition on a scale of 0 to 100.

For the next three years, the city resurfaces as many streets as possible with the funding allocated by council, in the order determined by the PCI and in a geographically equitable manner. Additional information about this process can be found at

Although city council has significantly increased the resurfacing budget, we are still making up for many years of deferred maintenance and much work remains. The 2016 inspection rated the entire road network as 58 out of 100. The city’s goal is to bring its roads to an overall score of 71, which is considered “satisfactory.” We estimate this would cost $7 million each year through 2022.

The condition of South Pitt Street is typical of the normal cycle of road deterioration and repair. Permanent asphalt cannot be used effectively in cold weather, so crews use a temporary product to fill potholes. Crews then return in warmer weather to make more durable repairs, typically with square patches. While patching can extend the life of a road, all roads require resurfacing at some point, typically every 12 to 20 years.

Finally, we want to address the writer’s point about recent changes to King Street for people who walk or bike. Safety improvements for pedestrians — such as new medians — occur because they are planned in conjunction with major road maintenance. After safety issues are addressed, the city prioritizes resurfacing through the process described above, and then uses that opportunity to help create more “complete streets” that improve safety and accessibility for all users.