Total Number of Lane Miles of Street Preventive Maintenance Completed
Preventive maintenance (PM) of existing pavements extends the life of the surfaces and reduces the amount of capital investment required on City streets each year. Asphalt overlaying, thin surface treatments and crack sealing existing surfaces are the primary components of the Public Works Department (PWD) PM program and help to reduce the number of unsatisfactory streets in the overall street inventory.
This measure is calculated by summing the total number of lane miles that receive a preventive maintenance method in order to extend the useful life of the street inventory.
FY 2015-16 Results
With 659 lane miles of preventive maintenance completed in FY 2015-16, PWD exceeded the goal of 572 lane miles by 15.2%.
Assessment of Results
This indicator is the total lane miles of various street preventive maintenance treatments, specifically crack seals, thin surface treatments, and asphalt overlays. Typically, between 8-10% of the street inventory receives preventive maintenance applications each year. An increase in demand from competing programs within Public Works and from City Council along with two significant weather events contributed to the program falling short of its goals in FY 2014-15.
Crack seal consists of sealing the cracks in the pavement with a sealant or asphalt-sealing product to prevent the moisture from entering into the base and subgrade material. Thin surface treatments consist of sealcoat, slurry seal, and fog seal, which are all used to increase skid resistance, fill existing pavement surface defects, or renew aged asphalt surfaces. Milling and overlay treatments require grinding up the existing asphalt and base material, removing it, and applying new pavement. The end result will be a much smoother driving surface. Overlay consists of a single layer of hot mix asphaltic concrete (minimum of 1½ inch thick, but typically 2”) used to level, waterproof, and restore the original street shape and ride.
Although work performed by the “in-house” workforce (crack seals, thin surface and asphalt overlays) met their target goals, contracted work could not be completed due to lack of funds. As a result, 60 lane miles of asphalt overlays and 140 lane miles of anticipated thin surface treatments were not completed that year. In FY 2015-16, the Department began the process to re-establish the funding and adjusted the goal based on the available funding. The Department also had a mid-year budget amendment for additional lanes miles to make up for the funding shortfall in FY 2014-15. These two factors lead to the increase in output in FY 2015-16.
In FY 2016-17, the Department increased funding to the program to address the maintenance need for the street network. The Department will utilize the FY2017-18 budget development process to review and determine the appropriate funding levels to achieve the desired performance goals and results.