Mobile Cross-Slope Measurement Method Using Lidar Technology

An effective cross slope facilitates drainage on highways and prevents hydroplaning. There is a need for transportation agencies to identify and measure road sections that have noneffective cross slopes so that timely corrective maintenance can be performed. However, the traditional manual methods used by transportation agencies to measure cross slopes with a digital level are time-consuming and labor intensive; these methods are not feasible for conducting a network-level cross-slope measurement. A proposed mobile cross-slope measurement method uses emerging mobile lidar technology that can accurately and effectively conduct network-level cross-slope measurement at highway speeds. The proposed mobile cross-slope measurement method uses emerging lidar technology (lidar calibration, data acquisition, region of interest extraction, and cross-slope computation). A sensitivity study was conducted to determine the key parameter (i.e., the region of interest interval) for the proposed method. The accuracy and the repeatability of the proposed method were critically validated through testing in a controlled environment. A case study demonstrated the capability of the proposed method. The results from the controlled test show that the proposed method can achieve desirable accuracy with an average measurement difference of 0.088 from the digital-level measurements and a desirable level of repeatability with a standard deviation of less than 0.038 in three runs. The results of the case study show that the proposed method can be operated at highway speed and is promising for the assessment of network-level cross-slope adequacy.