An Evaluation of Three Work Zone Intrusion Alarm Systems in California Provided Suggestions to Enhance Visual, Sound, and Sensor Components.

State Evaluation Report Examines Work Zone Safety.

Date Posted

Evaluation of Work Zone Intrusion Alarms

Summary Information

A work zone intrusion alarm (WZIA) system was tested to improve the safety of the current Caltrans Standard Plans for traffic control in work zones in Sacramento, California. The objective of this study was to evaluate the effectiveness of four WZIA systems and readiness for deployment in California work zones. The pilot testing took place at the Caltrans Maintenance Equipment Training Academy (META) testing facility in November 2018. The testing consisted of a trip hose used for vehicle detection, an alarm unit attached to the vehicle, and Personal Safety Devices (PSDs) for work zone workers. In this pilot, data and information were collected and documented to evaluate sound level and distance, operation, and functional characteristics. In addition, worker reaction time depending on vehicle speed when it passed the trip hose was studied.

The lessons learned from the project are summarized for the WZIA systems evaluated. 

  • Provide a visual alert and include multiple speakers and volume control to improve sound levels in all directions for the WAS system. Include a built-in belt clip and an audio alert that does not require the use of ear buds will be beneficial for the WAS PSD.
  • Consider an addition of a high-power repeater unit to increase the transmission range of the WAS system and improve functionality.
  • Incorporate a hook or collar in the WAS pressure sensor to change the elevation and improve reliable signal transmission distance.
  • Recess the manual activation buttons on the WAS hand-held remote and the PSD to prevent accidental alarm activation.
  • Incorporate battery level indicators on the WAS alarm unit, PSD, and pressure sensor.
  • Develop an alternative SonoBlaster mounting sleeve that can attach to the device to drop on to a traffic cone for quick installation.
  • Implement a sensor that can provide complete coverage over a wide area for the Intellicone system such as the pneumatic sensor employed by the WAS system.
Goal Areas

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