Evaluation and Validation of Automated In-Vehicle Data Collection System for Developing Roadway Alignments

Abstract

The Highway Safety Information System (HSIS) sponsored by FHWA includes crash and roadway inventory data from nine states for conducting safety studies. Whereas the initial choice of participating states was based on the presence of key roadway inventory variables, only two of those states currently have horizontal curvature data, and the data are limited. Given the known relationship between roadway curvature and safety, an objective of recent HSIS research was to improve on the available curvature data. A new algorithm makes use of in-vehicle data collected at highway speeds for the development of roadway alignments. Analysis of the algorithm focused on both consistency and accuracy. By using the Connecticut Department of Transportation's automatic road analyzer vehicle, repeated runs were made in both directions on each route selected for the consistency analysis. For the accuracy analysis, horizontal alignments were determined on the basis of survey data collected at the same locations. In general, the results from the PLV-HC software, which uses the azimuth data from the automated vehicle, prove that the data can be used to do a good job of identifying curves and tangents on a roadway. However, the data collected and the postprocessing software need improvement to capture the radius and length of each curve more consistently and accurately.