Evaluating and improving software for identifying trips, occupancy, mode and purpose from GPS traces.

Abstract

Over the past several years, the Institute of Transport and Logistics Studies at the University of Sydney has been developing software to process GPS traces and impute the trip ends, modes of travel, occupancy, and trip purpose. Conducting the GPS-only household travel survey for the Greater Cincinnati Area Household Travel Survey provided an opportunity to assess the accuracy of the existing software and to identify weaknesses and inaccuracies and propose changes to the software to overcome them. Initially, the accuracy of the software was assessed in the pilot survey. This analysis was then extended midway through the main survey and again at the conclusion of the main survey. The results of these assessments are documented in this paper. The paper concludes with a discussion of the accuracy achieved at this point in imputing trip ends, occupancy, mode, and purpose from GPS traces and the suitability of such data for travel demand modelling. The paper also suggests further research in this area that may provide even greater accuracy in the imputation of these attributes that are not measured directly by passive GPS devices.