Methodology to Identify Optimal Placement of Point Detectors for Travel Time Estimation

The purpose of this research was to develop a decision support methodology to identify the optimal locations of a finite set of point detectors on a freeway corridor to minimize the error in travel time estimation. The developed methodology, consisting of floating vehicle-based global-positioning system data collection, and use of a heuristic search technique (genetic algorithm)–based search tool, was shown to be effective in determining preferred detector locations for the chosen objective. Case studies of freeway sections in two Virginia regions were conducted to demonstrate the utility of the developed methodology. The writers found that the placement of detectors for the development of accurate travel time estimates will vary by location on the basis of specific conditions. Arbitrary, evenly spaced detectors do not necessarily result in accurate travel time estimates. With carefully placed detectors that are well maintained, travel time estimates can be derived with an acceptable level of accuracy from point detection, under incident-free travel conditions.