ICT research identifies improved models for IDOT to perform condition-rating survey analysis

Pavement management systems (PMS) assist decision makers in finding effective strategies for constructing, maintaining, and rehabilitating serviceable pavements over a given period of time for the least cost. Performance prediction models are an essential component of a PMS; they provide life expectancy estimates for pavements through cradle-to-grave monitoring of road conditions.

The Illinois Department of Transportation (IDOT) is responsible for the maintenance and operation of about 16,000 centerline miles of roadway across nine districts. IDOT’s Office of Planning and Programming conducts a Condition-rating Survey (CRS) to review the state’s highway network, provide overall condition of the highway system, and calculate pavement needs.

The CRS has been used by IDOT to evaluate the condition of pavements since 1974; CRS calculation and prediction models were developed in 1994-1995 to project future performance. This condition index is a numerical scale ranging between 1 and 9, which represent worst pavement rating and best road condition, respectively.

The calculation and prediction models denoted by the CRS were last reviewed and updated in 2006 through a research study (R27-013), Update Condition Rating Survey (CRS) Calculation/Prediction Models, conducted by the Illinois Center for Transportation (ICT) on behalf of IDOT. Laura Heckel, president of Heckel Engineering, Research, and Education, Inc. served as principal investigator and Yanfeng Ouyang, associate professor in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign (UIUC), served as co-principal investigator on the project.

Since that time, IDOT has expanded its use of pavement preservation treatments in an attempt to maximize pavement service life within dwindling budgets.  With the continued use of pavement preservation treatments and having several of these types of projects in place for many years, it was felt there may be enough data to develop initial CRS calculation and prediction models for pavement preservation treatments.

This led to the initiation of another ICT/IDOT research study (R27-150), Revised Condition Rating Survey Models to Reflect All Distresses, which aims to update and improve CRS calculation and prediction models.

“The existing CRS calculation and prediction models should be reviewed to verify reasonableness or to possibly improve the quality of the CRS calculation and prediction,” says Travis Lobmaster, Systems Performance Manager in IDOT’s Office of Planning and Programming, who is serving as Technical Review Panel chair for the project. “It is anticipated the research project will provide the Department with improved models to perform the CRS analysis and the needed tools to perform this analysis on pavement preservation treatments.”

Hasan Ozer, research assistant professor in the Department of Civil and Environmental Engineering at UIUC, is principal investigator for the current project. He explains, “Accurate prediction of CRS will help IDOT meet its long-term planning goals, efficiently allocate funds at the network level, and save taxpayer dollars while maintaining overall good road conditions.”

The project, which kicked off at the beginning of this year, is expected to be completed by the end of December 2016.