Transponder Program

Photo of the transponder

The transponder program allows commercial vehicles to bypass weigh stations by electronically verifying the legal weight, safety rating, and credentials as the commercial vehicle continues down the road at freeway speeds.

About Transponders

An essential part of making the electronic screening program work is the use of transponders. A transponder is a small electronic device attached to the inside of the windshield with a unique serial number. The transponder serial number is registered to a specific commercial vehicle in our database.

  • Roadside equipment is located approximately ½ mile before the weigh station
  • An antenna reads the transponder serial number to identify the commercial vehicle and look up the registration/cab card
  • Weigh-in-motion scales in the road calculate the weight and axle distances of the commercial vehicle
  • Electronic screening software checks the motor carrier’s safety rating, commercial vehicle registration information, weight and height for violations
  • The second antenna sends a signal back to the transponder
  • Green lights indicate no violations and the commercial vehicle may bypass the weigh station
  • Red lights indicate a possible violation and the commercial vehicle needs to report to the weigh station for a closer inspection
  • If the transponder light does not match the roadside signs follow the in-cab signal
  • If the transponder has no light follow the roadside signs

Red or green light will continue to flash intermittently for approximately 15 minutes. There is nothing wrong with the transponder. This is a built in protection for the carrier in case the driver is pulled over by law enforcement. The transponder signal allows the officer to verify the signal that was transmitted.

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