California Department of Transportation

VideoSync Portable Roadway Detector Evaluation System

VideoSync - What is it?

  • The VideoSync system consists of both hardware and software, each of which can be used independently.
  • The software syncs loop, radar, and other detector data with video and provides graphical and statistical tools for "ground truthing" the detector.
  • The associated hardware aids in collecting field data and can be used as a stand-alone surveillance system.
VideoSync Graphical User Interface VideoSync Graphical User Interface


Most projects in Caltrans are funded via the STIP or SHOP programs, to mitigate congestion and safety problems respectively. Therefore, Caltrans spent more than a decade developing PeMS, the world's largest online traffic database, which provides a multitude of graphical and statistical tools to assess congestion, accidents, and the relationships between them.

PeMS Graphics 1 PeMS Graphics 2
PeMS Graphics 3 PeMS Graphics 4

The biggest limitation to PeMS is the lack of quality data from loop and radar detectors. Hence, the need for VideoSync to calibrate and "fix" roadway detectors.

VideoSync - Motivation (Short Version)

  • ITS requires intelligence
  • Intelligence requires information
  • Information requires data
  • Data requires detection
  • Most roadway detectors are functioning sub-optimally
  • VideoSync contains many functions to make evaluation of detector data easier

Software Highlights

Hardware Highlights


  • VideoSync hardware and software can be used independently or conjunctively.
  • VideoSync generates verifiable, distributable, evaluations of irrefutable validity - seamlessly aggregating the micro to macro.
  • Evaluations easily distributed on CD or DVD for verification, eliminating ambiguity associated with prior evaluation methods.
  • VideoSync allows easy assessment of each and every detection site, where detector accuracy may vary with geometry, traffic, mounting, user settings, environment, and other factors.
  • Enhanced version may add more sophisticated time series statistics and image processing for further "ground truth" automation.

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