Ada County, Idaho began a proactive management plan for its rapidly growing network in 1996, when its average pavement condition was a 64 on the Pavement Condition Index - a C or “Fair” on other condition scales. Through an innovative zone rotation approach, a powerful predictive planning model, proactive taxpayer communication, and a broad treatment toolbox they’ve improved their average overall network condition by 20 points on the Pavement Condition Index.
BACKSTORY
The Ada County Highway District maintains a network of nearly 5,300 lane miles throughout the greater region surrounding Boise, Idaho. The area contains 27% of the statewide population and has a total annual budget of $15-20 Million.
Prior to 1995, Ada County, like many agencies, took a reactive approach to network management and spent most of their budget treating the worst roads in their network each year. With the overall network falling into worse disrepair, a rapidly growing population, and innovative leaders determined to be more proactive, they decided to implement a plan that would cover more lane miles and put the overall network on a path to improvement.
NETWORK APPROACH
As the population of Ada County grew, County leaders knew they needed to manage resident expectations while getting ahead of deteriorating pavement and keeping their good roads in good condition. In 1995, they introduced an innovative plan designed to systematically treat roads across the entire network, rotating through the network over the course of nine years. They began the program by simply treating every arterial, collector, and residential road in that year’s zone with a chip seal. Within one year, they saw a 3-point uptick in the network’s overall score on the Pavement Condition Index.
Research was proving that it was less expensive to maintain the network if they kept their good roads in good shape. By 2012 they had expanded to a 6-year rotation, with a commitment to treat roads “early and often.” They had integrated crack seal and fog seal into their planned zone maintenance, and over the last eight years have broadened their toolbox to also include Otta Seal, Microsurfacing, Slurry Seal, Cold In-Place Recycling, Mill & Inlay, Full Depth Reclamation, and Cement Recycled Asphalt Base Stabilization.
Another key part of their plan was proactive communication to bring the community along with them. From presentations to electeds, to mailers, doorknockers, and an interactive map they make sure residents and elected officials alike understand what treatments they’re doing, why they’re doing them, and when they can expect their roads to be addressed.
“Pavement is our most valuable asset.” Scott T. Forrey, P.E. Pavement Management Engineer, Ada County Highway District
ADA COUNTY TODAY
Today, Ada County’s roads have an average Pavement Condition of 80. They treat 450 - 500 lane miles each year. They pay close attention to the longevity and equivalent annualized cost of each treatment, and are focused on ensuring they select the right treatment for the right road at the right time.
They share their lessons learned, key commitments, how they stay apprised of industry trends, and a behind-the-scenes “how we did it” look in a free webinar on RoadResource.org/webinars.
“It’s an investment. Putting our money into preventative maintenance has shown positive long term effects on our roads.” - Lloyd Carnegie, Maintenance Manager, Ada County Highway District
View PPRA's website here.
