A Pavement Management System has been defined as “A coordinated set of activities, all directed toward achieving the best value possible for the available public funds in providing and operating smooth, safe, and economical pavements” (NCHRP Report 215).
WSDOT has a rich history of Pavement Management System implementation, dating back to the 1970’s. This long tradition has made WSDOT one of the national leaders in this area. The FHWA has published a document titled: “Pavement Management Systems – The Washington State Experience” that summarizes WSDOT experience and calls the WSPMS a “model” Pavement Management System (FHWA Report IF-08-010).
In 2015, Washington's Joint Legislative Audit and Review Committee (JLARC) finished a 2 part report, and concluded that the Pavement Management at WSDOT is reliable and uses industry best practices.
Key components of the Washington State Pavement Management System (WSPMS) are data analysis, WebWSPMS, and data collection, distress identification and friction testing.
WebWSPMS is WSDOT's principal application for pavement asset management. It can be accessed through the WSDOT intranet. If you are not a WSDOT employee and would like information about WebWSPMS, please read the WebWSPMS Overview or contact the WSPMS Administrator at firstname.lastname@example.org.
WSDOT examines the condition (distress level) of existing roadways to inform pavement designers about base or subgrade problems, inadequate structure, insufficient material properties, or increased truck loading to name a few.
Pavement distress is collected using WSDOT's Pavement Distress Identification Van. The van is equipped to record pavement profile (ride, faulting, and rutting) and video images of pavement surfaces. The data can be collected at highway speeds, significantly enhancing the accuracy of the data collection process. It also provides a variety of research and analysis options concerning pavement performance.
The data collected by the van is then processed by trained technicians, based on the Pavement Surface Condition Rating Manual (pdf 3.32 mb). The processed data is then analyzed and included in the WSPMS.
Road Rater Van featured on King 5 News
In general, the friction of most dry pavements is high (good). However, the same pavement sunder wet conditions can present a friction problem. Surface friction data allows WSDOT to identify potential low friction pavements that, in conjunction with accident history and roadway geometrics, are used to minimize wet weather skidding accidents.
WSDOT measures surface friction every two years on all state-maintained roads using a friction testing truck and trailer. To conduct friction tests, water is applied to the pavement surface in front of the test wheel on the trailer. A brake is applied to the test wheel and when the wheel locks, the drag and load (horizontal and vertical forces) are measured to derive the amount of surface friction.