Time Dependent Network Coverage: A Method to Estimate the Minimum Required Reporting Vehicle Fleet Size

Abstract

Probe vehicles with smart phones or other advanced technologies are attractive options for collecting real-time traffic data. In this paper, a method is proposed to estimate the minimum number of equipped vehicles needed to completely cover the network within a specified updating period considering time dependent link travel times. The method uses a traverse indicator, which is a function of a travel time factor, coverage factor, number of times a link has been traversed, and link travel time. The approach is applied to two network structures (radial and grid) to test the sensitivity of the results to network structure, number of origins, travel time and coverage factors, and the updating period. Assuming travel time and coverage factors equal to 0.1 and 0.9, respectively, in the grid network and both equal to 0.5 in the radial network produce minimum fleet sizes. Increasing numbers of origins and updating periods generally yield lower fleet sizes.