Work Zone Performance Measurement Using Probe Data
Executive Summary
Work zones present problems when it comes to performance measures since, by definition, they are not fixed in space or time. This reduces the value of data generated by traditional fixed sensors – fixed sensors may not be located where needed to monitor work zone traffic or may be out of service because of work zone activities. Probe data provides an alternate means of obtaining data on work zone traffic conditions to support work zone performance measures by gathering data directly from moving vehicles. This probe data can either be collected directly (e.g., by placing Bluetooth detectors at key locations) or obtained from a number of commercial providers that specialize in the collection and distribution of probe data.
The potential for probe data to improve work zone performance measurement is significant; but, implementation is not easy. Commercial probe data providers have focused on probe data products for normal traffic management operations and have little experience with the data needs specific to work zones. Most work zone practitioners have limited experience with probe data. Consequently, knowledge of the ability of probe data to support work zone management needs is limited. This report aims to address these problems and provide practical guidance to work zone program managers on how to take advantage of probe data resources to support their work zone performance measure needs. Topics covered include:
- An overview of probe data and the advantages and disadvantages of probe data sources relative to traditional fixed sensors.
- Identification of when and how to use probe data sources to support work zone performance measures, including identifying which work zone performance measures can be supported by different types of probe data sources.
- Characterization of the applicability of different types of probe data to help manage different types of work zones.
The report also includes a detailed case study of a pilot project conducted by the University of Maryland Center for Advanced Transportation Technology for Maryland State Highway Administration. This pilot project assessed the adequacy of available probe data sources to support work zone performance measures and implemented a web-based system that uses probe data to assess work zone performance measures. This project provides detailed examples of performance measures produced from probe data.
The last part of the report provides overviews of a number of other projects and activities that either used probe data for work zones or assessed characteristics of probe data that might be helpful to work zone practitioners. Appendices provide information on (a) the future of probe data and how the evolution of probe data will impact its applicability to work zone performance measures and (b) simulation results that investigate the effectiveness of Bluetooth detectors as a source of work zone traffic data.
There have been numerous successful examples of using probe data to support work zone performance measures. Most of these examples focus on using probe data to measure work zone travel times, though there are also examples of using probe data to help monitor queue formation and to detect changes in route choice. The net result suggests that the time has come for work zone practitioners to consider taking advantage of probe data sources.
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