Pavement Management for
Metro Nashville & Davidson County

The metropolitan government of Nashville and Davidson County, a single entity responsible for both the County and the City, maintains approximately 2,400 centerline miles of roadways encompassing many different street types, from wide urban arterials to two-lane rural roads.  ARA helped Metro’s Paving Department modernize their pavement management system with new software, new data collection methods, and improved procedures.

Pavement Management

In 2002, ARA performed a complete survey of Metro’s paving network, including the alleys found in many of the urban locations within Davidson County.  Since then, ARA has performed condition assessments on the pavement network annually; half of the network is surveyed each year.  Pavement surveys are performed in accordance with ASTM D 6433, with modifications to meet the needs of Metro’s paving staff.  For example, an automated raveling survey is performed that determines the level of raveling on the pavement based on Mean Texture Depth (MTD), as measured by ARA’s Digital Survey Vehicle (DSV). 

In 2006, it was determined that the methods used to evaluate raveling were not meeting Metro’s needs.  In response, ARA and Metro developed a relationship between MTD and raveling and use that measurement along with pavement age to determine which roads are eligible for this kind of rehabilitation.

Strategic Planning

ARA and Metro also have generated a publicly available, detailed plan for the maintenance of Metro’s pavement network.  This plan explains the basics of pavement management, the software and hardware tools used, and the regulations Metro is required to address (local reporting requirements and GASB-34).  The plan also discusses in detail the procedures used to select projects and the different rehabilitation options available to Metro engineers.  These options consist of tried-and-true methods used in Metro Nashville for years, state-of-the practice paving methods used throughout the region, and new paving methods tested on samples of Metro pavement. The complete guide can be downloaded at
http://mpw.nashville.gov/Row/Paving/MasterPlan.aspx.