Outsourced probe data effectiveness on signalized arterials^*

^*An earlier version of this paper (Sharifi et al., 2016) was presented at the Transportation Research Board meeting in 2016.

ABSTRACT

This paper presents results of an I-95 Corridor Coalition sponsored project to assess the ability of outsourced vehicle probe data to provide accurate travel time on signalized roadways for the purposes of real-time operations as well as performance measures. The quality of outsourced probe data on freeways has led many departments of transportation to consider such data for arterial performance monitoring. From April 2013 through June of 2014, the University of Maryland Center for Advanced Transportation Technology gathered travel times from several arterial corridors within the mid-Atlantic region using Bluetooth traffic monitoring (BTM) equipment, and compared these travel times with the data reported to the I95 Vehicle Probe Project (VPP) from an outsourced probe data vendor. The analysis consisted of several methodologies: (1) a traditional analysis that used precision and bias speed metrics; (2) a slowdown analysis that quantified the percentage of significant traffic disruptions accurately captured in the VPP data; (3) a sampled distribution method that uses overlay methods to enhance and analyze recurring congestion patterns. (4) Last, the BTM and VPP data from each 24-hour period of data collection were reviewed by the research team to assess the extent to which VPP captured the nature of the traffic flow. Based on the analysis, probe data is recommended only on arterial roadways with signal densities (measured in signals per mile) up to one, and it should be tested and used with caution for signal densities between one and two, and is not recommended when signal density exceeds two.

KEYWORDS:

• arterial
• interrupted flow roadways
• outsourced probe data
• slowdown analysis
• sampled distribution method
• travel time

Acknowledgement

This research was part of the Vehicle Probe Project funded by the I-95 Corridor Coalition. Also, the research team would like to express its gratitude for the assistance it received from the state highway officials from various Coalition members during the course of this study. Their effort was instrumental during the data collection phase of the project. This paper would not have been completed without their help.