Emergency Vehicle Preemption (EVP) systems provide great benefits for emergency responders by improving their response time and helping them save lives. Fire and EMS vehicles are equipped with an infrared emitter enabling emergency response teams to preempt the traffic signal and to extend the traffic signal timing to allow these vehicles to navigate congested intersections faster and safer.
When preempting coordinated traffic signals, it removes the preempted signal from the coordinated system, so that the signal can respond to the emergency vehicles preemption call and give the approaching emergency vehicle a green light. This process does significantly affect traffic flow progression. The county's smart traffic signal system automatically recognizes that the signal is out of step and starts the process of realigning the signal back into coordination. Depending on how far the traffic signal is out of step, this process can take up to five traffic signal cycles which is approximately 10 minutes.
For a brief video explaining the system click on the image below:
Confirmation Beacon (white light)
Confirmation beacon lights are intended to communicate to approaching emergency vehicle drivers the status of the traffic signal. These are different than the Blue Lights that are in the City of Naples (see description below). There are three stages of operation for the lights:
Stage 1, normal status is, when the light is dark. The confirmation beacon will be in this state the majority of the time and the system is considered to be in the listening mode.
Stage 2, a solid white light on, communicates to approaching emergency vehicles that the traffic signal preemption system has received their infrared signal and it is processing their call. The time to process the vehicle preemption call varies depending upon the phasing (i.e. turning and through movements) that the traffic signal is serving at the time when the preemption call is received.
Stage 3, a flashing white light, communicates to approaching emergency vehicle drivers that the traffic signal is currently processing an emergency vehicle preemption call on one of the other approaches to the intersection and, therefore, their call will not be processed until the other call has expired (the other emergency vehicle went through the intersection).
The blue lights that one sees mounted on the mast arms on US 41 throughout the City of Naples are an aid to law enforcement officials to determine if a motorist has run a red light. In Florida, as it may be elsewhere in the country, a law enforcement officer must physically observe that a motorist has run a red light in order to legally issue a citation to the offending motorist. The blue lights are connected to the red signal indications. If an officer observes the blue light at the approach to an intersection and a motorist enters the intersection from that approach, the law enforcement officer immediately knows that the motorist has run a red light due to the lit blue light.