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Signal Preemption Systems

What does a traffic signal preemption system do?

These electrical devices allow a traffic signal to respond to the approach of a particular type of vehicle or the occurrence of an unusual condition at or near a highway intersection.

Such systems are designed to:

  • Increase safety,
  • Reduce emergency response times and
  • Enhance public transit operations.

When can preemptions systems be used?

These systems may be used to preempt normal traffic signal operation by the approach of emergency vehicles, or may be used to modify the length of the green light time, allowing for more efficient transit operation.

How do these system work?

A signal mounted preemption system requires the installation of a receiving device within the traffic control signal cabinet that responds to a remote triggering device attached to specific authorized vehicles.

  • Signal mounted systems generally allow vehicles traveling in the same direction as the emergency vehicle or bus to receive, or continue to receive, a green indication.
  • In the case of emergency vehicle preemption, the green indication provides an opportunity for motorists to clear the road ahead of the advancing emergency vehicle.

Applying for Signal Preemption

Installation and operation of signal mounted systems are at the discretion of the traffic control signal owner. Emergency providers and transit companies must apply for authorization to own and operate remote signaling devices.

To apply, interested parties should provide the information requested on the appropriate form below and submit it to the ODOT region where the system will be operating.

Review Process

The region traffic manager will review the request and submit a recommendation to the state traffic engineer. The state traffic engineer has approval authority for all requests.

Emergency vehicle preempting a signal  

Contact the Traffic Operations Unit

4040 Fairview Industrial Drive SE, MS 5
Salem, Oregon 97302
Phone: 503-986-3589
Fax: 503-986-3749

Regional Contacts

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