United States Department of Transportation
i
Roadway Traffic Data Collection from Mobile Platforms, Technical Summary
-
2017-07-28
[PDF-1.17 MB]
Details:
-
Creators:
-
Corporate Creators:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Corporate Publisher:
-
NTL Classification:NTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATION;NTL-OPERATIONS AND TRAFFIC CONTROLS-OPERATIONS AND TRAFFIC CONTROLS;
-
Abstract:This project empirically investigates the traffic flow estimations from different types of data collected from two types of mobile platforms – transit buses in service operations and a van driven to emulate bus coverage – that repeatedly traverse roadway segments. At the root of this approach are probe vehicle-based studies and, in particular, the moving observer method. Conventional probe vehicle and floating car studies have been commonly used to collect travel time, delays, and stops, and they are becoming increasingly common for real time travel time measurement. Within the probe vehicle literature is the moving observer method. As originally conceived, the moving observer method suffers from two major limitations. First, it requires a dedicated vehicle and two people – someone to drive and someone to count vehicles. Second, a single pass of the moving observer over a roadway segment will be brief and result in a short-duration observation that is subject to high variability in flow conditions from, for example, nature of travel demand, signal phasing, major or minor incidents, and behavior of drivers of detected vehicles. Using transit buses as sensing platforms can mitigate these limitations. The transit vehicle is already in service; therefore, a dedicated vehicle and driver are not required. If sensors are mounted on the platform, the need for a data collector is also eliminated. Transit companies are increasingly installing inward and outwork looking video cameras on their buses, primarily for safety, security, and liability reasons. If the video data can be used for traffic flow estimation, as is investigated in this study, the need for additional sensors is also eliminated. Each individual pass of the platform will still result in a short-duration observation, but the repeated (many times per day, days per week, weeks per year) traversal of the same road segments by sensor-equipped buses can lead to multiple, independent observations that can be aggregated to reduce the effects of the single pass, short-duration observations and potentially yield meaningful traffic flow estimates. A modification of the moving observer method is needed to estimate the flow rate from data that would be obtained from a bus platform on a transit route. This method is described in section two of this report. In the third section the various data sets collected from transit buses in regular operations and from a sensor-equipped van that was driven over segments traversed by the buses are presented. The implementation issues used to process the different data sets into input data for use with the modified moving observer method are also presented in this section. In the fourth section empirical results are presented. Comparisons among the estimated flows obtained from different types of data, different time-of-day periods, and different periods of the year support the reasonableness of the estimated results and, therefore, of the ability to estimate reasonable flow rates by using the modified moving observer method with data obtained from a mobile platform that repeatedly covers road segments. In the final section, it is argued that further investigation of the present results is warranted, as are additional empirical studies, but that the results obtained in this study and the potential of using available video from transit bus fleets also motivate pursuing issues involved with operational implementation of the ideas developed in this project.
-
Format:
-
Funding:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
