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Aggregating Traffic Volumes Estimated from Video Imagery Collected on Repeated Bus Passes: Empirical Evaluation of Different Approaches

Charmchi Toosi, Shahrzad
http://rave.ohiolink.edu/etdc/view?acc_num=osu1629563563291726

Abstract Details

2021, Master of Science, Ohio State University, Civil Engineering.
To expand spatial-temporal coverage of data collection for estimating traffic volumes, it has been proposed to use video data from transit buses. Transit buses are already covering the major roadways in an urban network. Many buses already have cameras deployed for other purposes, but which observe vehicles on a roadway segment that can conceivably be used to estimate traffic volumes. The volumes estimated in this way are of short duration, however, and therefore are likely to give an unrepresentative estimate of traffic volumes over time periods of interest. To get a good estimate of traffic volume for an estimation period, the multiple volume estimates obtained from the individual passes within that period can be aggregated. This thesis proposes and evaluates different methods to aggregate the volumes derived from individual bus passes. Different aggregation approaches, which are categorized into “discrete time interval” and “continuous time’’ approaches, are presented. The first category, representing the first general approach, aggregates individual bus pass volumes by taking their arithmetic average in discrete time intervals. The second category considers bus passes as flow rates that can be integrated over continuous time to determine a volume estimate in a specified time interval. In one implementation of this continuous time category, considered the second general approach, a benchmark interpolation of the individual bus pass flow rates is used to determine the flow rate function. A different implementation of continuous time aggregation, which is considered the third general approach, attempts to smooth the flow rate function by using a “moving median time window” technique before integrating the rates over time. Evaluation of the approaches is conducted using empirical video data collected from Campus Area Bus Service buses serving The Ohio State University and concurrently collected road tube counts provided by the Mid-Ohio Regional Planning Commission. Volumes that have been previously estimated from the individual bus passes are used as one set of data (Data Variant 1) that serves as input to each of the three approaches. A second set of data (Data Variant 2) used as input to each of the three approaches consists of volumes from individual bus passes that have been transformed through a regression model. The combination of the three approaches and two Data Variants leads to six “Methods,” and the evaluation results indicate that the aggregation Methods based on integrating the flow rate function systematically improve the volume estimates compared to aggregation based on arithmetic averaging. For some comparisons the moving median approach performs better, while for other comparisons the moving median approach performs worse. Other consistent results are seen in the empirical evaluations. Specifically, regardless of the Method: there is no evidence of systematic over- or underestimation of period volumes when using the bus video data; lower relative errors are obtained for longer (specifically, 60-minute) estimation periods than for shorter (specifically, 15-minute) estimation periods; and transforming the individual bus pass volumes through a regression model calibrated on an independent data set leads to better traffic volume estimates.
Mark McCord (Advisor)
Andre Carrel (Committee Member)
Rabi Mishalani (Committee Member)
154 p.
Civil Engineering
Traffic volumes; Aggregating traffic volumes; Video imagery; Bus pass; Video data Collected from bus pass

Recommended Citations

Citations

  • Charmchi Toosi, S. (2021). Aggregating Traffic Volumes Estimated from Video Imagery Collected on Repeated Bus Passes: Empirical Evaluation of Different Approaches [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1629563563291726

    APA Style (7th edition)

  • Charmchi Toosi, Shahrzad. Aggregating Traffic Volumes Estimated from Video Imagery Collected on Repeated Bus Passes: Empirical Evaluation of Different Approaches. 2021. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1629563563291726.

    MLA Style (8th edition)

  • Charmchi Toosi, Shahrzad. "Aggregating Traffic Volumes Estimated from Video Imagery Collected on Repeated Bus Passes: Empirical Evaluation of Different Approaches." Master's thesis, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1629563563291726

    Chicago Manual of Style (17th edition)

osu1629563563291726
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This open access ETD is published by The Ohio State University and OhioLINK.
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