Why do Roads Deteriorate?
All roads begin deteriorating as soon as they are built; subjected to water, freeze/thaw cycles, solar radiation, as well as varying traffic loads. Typically, pavements perform well under loads until a particular point in their life span and then deteriorate precipitously and eventually fail. The road is then either rehabilitated or totally reconstructed.
Why a Proactive Approach?
Demands on the road network continue to rise with increased traffic volumes. At the same time, funds available for road maintenance grow ever tighter. Pavement preservation has proven to be very cost effective. A more efficient and cost-effective approach is needed to maintain roads and meet the expectations for safety, ride quality, and optimum traffic flow, while protecting the capital investment in the transportation network.
Pavement preservation strategies can reduce or eliminate:
- The need for costly, time consuming rehabilitation or reconstruction of roads that have reached or exceeded their useful lives;
- Traffic disruptions and;
- Work zone danger, because the maintenance treatments can be applied more quickly than full reconstruction.
Why not “Worst First”?
Traditionally, transportation agencies have allowed the structural condition of a road segment to deteriorate to a fair or good condition before taking action to rehabilitate or totally reconstruct the road. The logic behind this process was to achieve the most useful life out of a road – typically 15 to 20 years for an asphalt segment – and thus maximize the required capital investment.
There are three problems with this reactive approach to road maintenance:
- Motorists experience progressively worse driving conditions as the road segment ages;
- The rehabilitation or total reconstruction process is expensive, and;
- Major reconstruction is disruptive to traffic flow.
The “worst first” method silos your budget into individual projects and only addresses the worst piece of pavement while ignoring the majority of your network, which continues to decline annually. By neglecting the majority of your pavement and only treating the worst piece of pavement first, your total budget is depleted, the overall Pavement Condition Index (PCI) decreases, and your network weakens over time with no plans in place for improvement.
The “balanced approach” employs strategic pavement preservation treatments. Over time, you improve the quality of your entire roadway network as a whole if you apply the right treatments, to the right roads, at the right time. By following the “balanced approach” method, your budget will be maximized and your entire roadway network’s PCI will increase and improve year after year.
Implementing Pavement Management System at Knox County
Modern public works agencies have been transitioning to deploy Pavement Management System (PMS), which "is a systematic method for routinely collecting, storing, and retrieving the kind of decision-making information needed to make maximum use of limited maintenance (and construction) dollars" (APWA). Knox County, in the effort to provide our taxpayers with the first-class service, is implementing a data-driven method to prolong the lifetime of our roadways as well as improve safety for our residents while traveling.