GPS—Rapid Solutions for Transportation Management

The use of global positioning systems (GPS) as a survey tool can bring rapid solutions for transportation management. GPS can be an efficient cost‐effective, and accurate method of obtaining positional data, as reported by Henderson and Quirion in 1988. Field conditions can limit the use of GPS. To use GPS effectively requires innovation, expertise, and experience on the part of surveyors, as noted by Craymer et al. in 1990. GPS data combined with a total station data were used to provide control along a 27.5 km (17.1 mi) section of the Santa Monica Freeway, in California. A total of 54 primary stations were positioned with GPS and 203 secondary stations were positioned with a total station. The static method was used in lieu of the kinematic method to position primary stations. For reasons explained in the paper, it would have been difficult if not impossible to maintain lock on the satellites during the progress of the survey and collect valid data for positional computation, as reported in Coad, in 1988. The survey control was completed in order to digitize the traveled edges of the freeway. The digitizing and compilation of maps was completed directly from the photos and not by a stereo compilation.