Innovative Solutions for America’s Roads: Targeted Overlay Pavement Solutions (TOPS)

The United States is currently facing an $852 billion highway repair backlog, the pavement component of which is $511 billion. Compared to pavement reconstruction, using asphalt or concrete overlays can be a cost-effective solution to helping address this highway repair challenge by extending pavement life and increasing load-carrying capacity while also improving safety, mobility, and user satisfaction.

During Every Day Counts round six (EDC-6), FHWA promoted Targeted Overlay Pavement Solutions (TOPS) to State departments of transportation (DOTs) and local agencies as a way to maximize their highway repair investments by improving on conventional overlay methods and including new overlay materials and techniques.

The EDC-6 TOPS team also set out to do something no other EDC team had done before—communicate and encourage the deployment of 11 products as part of one EDC initiative. EDC-6 outreach offered an opportunity to educate agencies and stakeholders about a collection of asphalt and concrete overlays that provide proven long-life performance under a wide range of traffic, environmental, and existing pavement conditions.

“Prior to the start of this EDC initiative, we identified some proven, yet underutilized types of pavement overlays,” said TOPS EDC Team Co-leader Tim Aschenbrener. “We were able to explain appropriate project selection practices, cost-effectiveness, performance, and reliability. I’m excited about the number of agencies that have deployed different types of overlays they had not previously tried but gave another look thanks to EDC.”

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Asphalt TOPS Products

• Asphalt rubber gap-graded
• Crack attenuating mix
• Highly modified asphalt
• High-performance thin overlay
• Open-graded friction course
• Stone matrix asphalt
• Ultra-thin bonded wearing course

Concrete TOPS Products

• Bonded concrete on asphalt
• Unbonded concrete on asphalt
• Bonded concrete on concrete
• Unbonded concrete on concrete

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EDC Outreach

Case studies and research presented as part of EDC outreach efforts piqued the interest of States and local agencies. They learned how the New Jersey DOT’s use of highly modified asphalt (HiMA) overlays over a decade increased “good condition” roads from 12 percent to 40 percent and how research in Iowa suggests concrete overlays will last 35 years—15 years longer than the previous life expectancy.

Other successful practices shared include research by the Florida DOT that showed the use of HiMA was significantly more effective at preventing rutting as the control mix and increased structural capacity by up to 20 percent, as well as a Delaware DOT concrete overlay that has required only minor maintenance during 30 years of service to maintain a smooth ride. Additionally, Texas DOT research showed that properly designed asphalt overlays with crack-attenuating mix may reduce the number of reflective cracks and slow the cracking process by up to 50 percent.

Success Stories

Forty-one States participated in the TOPS EDC-6 initiative—26 focused on asphalt overlays, 15 learned more about concrete, and 13 participated in both. As a result of EDC-6, 22 States advanced to a new phase in the implementation process from “not implementing” to the development, demonstration, assessment, or institutionalized phase. Nineteen States have institutionalized TOPS products by incorporating at least one overlay type as a standard fix option within the agency’s pavement management program.

Thanks in part to EDC, Utah DOT used HiMA at a port-of-entry weigh station where heavy trucks and high-volume traffic were causing pavement issues. “Word got out about this successful demonstration project, and now they’re on track to use half a million tons of HiMA this year,” said Aschenbrener. Utah DOT researchers believe HiMA could extend pavement service life by up to 5 years.

EDC introduced the Arizona and New Mexico DOTs to stone matrix asphalt (SMA) and both are now working toward making it their go-to asphalt overlay, and the Montana DOT now plans to try a project with HiMA and another with SMA.

California, Pennsylvania, Nevada, and Virginia showed special interest in concrete overlays by scheduling in-person workshops. “I think our outreach efforts to create awareness of the viability of concrete overlays have encouraged many States to rethink their maintenance strategies and take steps toward adding concrete overlays as another asset management tool,” said TOPS EDC Team Co-leader Robert Conway.

Ongoing Efforts

The formal EDC-6 innovation cycle ended in December 2022, but TOPS implementation continues.

“We can tailor training for agencies that may need it due to staff turnover, want to re-evaluate the cost-benefit analysis of overlays, or need assistance making overlays standard practice,” said Conway.

Resources are also available on the TOPS webpage including articles, brochures, case studies, how-to reports, one-pagers, and webinars.