Prepared by David Humphrey, Ohio Department of Transportation
The Ohio Department of Transportation (ODOT) is implementing a near-project level pavement management system. One of the key elements that made the system possible is our rich history of detailed distress data. In the early to mid 1980’s, ODOT developed a pavement condition rating (PCR) system. The PCR is based on a visual inspection of the pavement and rating the distresses for both severity and extent. ODOT has used the PCR to rate all state maintained roads on an annual basis since 1986.
The PCR consists of up to seventeen distresses with a maximum deduct value for each distress resulting in a zero to 100 value, with 100 being the best condition. Unique distresses exist for each pavement type: flexible, composite, and jointed concrete (Ohio no longer has any exposed continuously reinforced concrete).
To maintain consistency, a manual was developed explaining each distress type, the different extents, and the different severity levels with pictures of representative distresses. In addition, we have used a small group of permanent employees to do the ratings over the years. Currently the entire state is rated each year by three raters, each with over 20 years of experience.
Using the long and detailed distress history, we were able to develop performance curves for each distress for each of the typical pavement construction and maintenance activities (chip seal, micro surfacing, overlays, complete replacement, etc.). With the distress performance prediction curves, we were able to develop detailed decision trees as the basis for the pavement management system.
While the experience of the raters is a great asset, with all of them nearing retirement eligibility, it has also become an area of great concern. To prepare for possible retirements, ODOT initiated a research project to see if an automated system could reproduce our PCR. Three vendors participated in the research and in the short time available, none was able to do better than a 20 percent match of the manually rated PCR.
ODOT is continuing to work with one of the vendors to try and improve the automated collection. The hope is we may be able to get a nearly 80 percent match with the manual ratings. Some distresses, particularly at the low severity levels, are very difficult for the automated systems to detect with current technology. Our hope is the technology will continue to improve. In the meantime, we are faced with the possibility of converting to a new PCR. If we are able to collect both manual and automated PCR concurrently for a sufficient number of years, we may be able to develop a correlation between the two. If not, we are faced with the prospect of losing all our historical PCR data and the performance curves developed from that data.
Automated distress collection is safer for the raters, may be required by federal reporting requirements, provides data for mechanistic-empirical pavement design, and should improve with time, rather than retire. ODOT faces some big challenges if we are to change the way we’ve been doing business for the last 30 years.
For more information, please contact David Humphrey at David.Humphrey@dot.ohio.gov