To manage events associated with highways, data systems have been developed to store relevant event information. To reap the full benefits of geographic information system technologies, the relative locations can be integrated into a linear referencing system. The objective of this paper is to present a methodology for building a highway linear referencing system by applying preexisting marker measurements to a digital street network. The system was developed for locating motor vehicle collisions in California and resulted in improved accuracy compared to a previously developed system. Nearly 50 percent of the relative collision locations based on the two different systems were within one meter of each other, but 4.1 percent were greater than 1,000 meters. Differences in collision locations were likely because of improved accuracy for (1) an increased number of reference markers were used, (2) all route realignments were accounted for, and (3) all previously identified errors were corrected.
January 1, 2013