Measurement of Wheel Wander Under Live Traffic Conditions

Resumo

A critical parameter to measure for any type of pavement structural analysis is the precise location of the applied load. Under live traffic conditions the placement is random (termed wheel wander) and is important to characterize since it defines the transverse location and severity of pavement distress. As more test roads are built with embedded instrumentation to support the calibration and implementation of mechanistic-empirical (M-E) pavement design, the load placement relative to the instrumentation must be determined. Also, it is necessary to assess whether the wheel wander under test conditions is representative of open-access facilities. In this research, a lateral-position measurement system, comprised of independent axle sensing strips, was installed at the National Center for Asphalt Technology (NCAT) Test Track to measure wheel wander of the  traffic. The Test Track is a 1.7 mile (2.7 kilometer) cooperative research test road trafficked by five tractor-trailers operated by ten drivers over two shifts per day. This paper details the lateral-position measurement system, the installation process, the calibration process and the algorithms to compute lateral offset. Data collected over two trucking shifts are presented, comprised of over 3,000 axle passes, and indicate a normal distribution of wheel wander at the Test Track having a standard deviation of 8.6 in. (21.8 cm), consistent with measurements made at openaccess facilities.