Raleigh pavement management program

Opportunity

Raleigh, North Carolina is one of the fastest-growing cities in America. The city’s Transportation Department maintains over 1,100 miles of roadway, and average daily traffic can see up to 40,000 vehicles per day. The city predominantly uses asphalt for paving, and the estimated replacement cost is over $700 million.

The city once used an approach where the roads in the worst conditions were fixed first. However, transportation leaders determined this approach wasn’t cost-effective. Allocating funds to the worst parts of the roadway network allowed the parts in good condition to deteriorate over time.

Solution

To improve the city’s roads on a limited budget, Mott MacDonald was hired to implement a pavement management system (PMS). We developed a comprehensive strategy to switch from visual inspection of pavement condition to automated data collection.

Crack density, which measures the total crack length per unit area, was the primary pavement metric used to generate automated data. Crack density measurements were 90% accurate and 90% repeatable over the data collection cycle. This data collection method along with the pavement management system analysis allowed the city to see which streets need prioritization.

The project team configured the PMS to examine different funding strategies and treatment options for the roadways. The pavement management program consists of low-cost preservation and maintenance treatments such as chip seal, fog seal, rejuvenation, crack pour, and localized patching, reasonable expenditures on mill and overlay, and reconstruction plans for streets falling under specific thresholds.

Outcome

Raleigh is already seeing the benefits from this pavement management program. The preservation efforts provide streets that are well-maintained and safer for commuters. Improved travel times and fewer construction-related work closures may also have positive environmental benefits.

Raleigh also implemented a pilot project to use a titanium dioxide additive in pavement rehabilitation process to cut down on carbon emissions. This project won a Cleantech Impact Award for Transportation from the Research Triangle Cleantech Cluster, a state industry initiative of government, academic, and business leaders.