Emergency Vehicle Traffic Preemption Systems

JAS

Flashlight Enthusiast
Joined
Nov 16, 2002
Messages
1,303
Location
Rosemount

JAS

Flashlight Enthusiast
Joined
Nov 16, 2002
Messages
1,303
Location
Rosemount
Planning on a DIY build project...?

Not hardly. My wife sent me a text this morning and she had the semaphores change due to an Opticom. She didn't see any emergency vehicles, but it could have been an unmarked vehicle.

I found the high priority, low priority, and "audit" rates. I didn't even realize that there is an audit!
 

-Virgil-

Flashaholic
Joined
Mar 26, 2004
Messages
7,802
It can be a real rabbit hole deal, chasing after all the scarcely-documented features and modes on stuff like this. They understandably try to keep it out of the public eye. (No, I am not holding out on you; at this point you know more about it than I do.)
 

JAS

Flashlight Enthusiast
Joined
Nov 16, 2002
Messages
1,303
Location
Rosemount
A good friend of mine formerly did emergency vehicle equipment installations. He knew about the high priority and low priority, but the "audit" rate was new to him.

I definitely learned some things from this, too. I simply thought that they were designed for emergency vehicles, so when I read that they were originally designed for mass transit, it was something of an "a ha" moment, so to speak.
 

Alaric Darconville

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Sep 2, 2001
Messages
5,377
Location
Stillwater, America
A good friend of mine formerly did emergency vehicle equipment installations. He knew about the high priority and low priority, but the "audit" rate was new to him.
The audit rate may be useful to find the most common routes of emergency vehicles, or for an individual vehicle to add timestamp information to intersection crossings while following another vehicle, or any other number of things where you want to log that you went through the intersection but didn't preëmpt the signal.

I'd recommend that each preëmption device also send a serial number so it's easier to tell who is using it. Of course, there may be someone trying to make their own device, but instead of rejecting them, logging the non-serialized preëmption and activating a camera (for example, the red light camera) may help track down who is doing this unlawfully. Rejecting non-serialized/unknown serial units could cause more of a problem than it solves.
 

ak645

Newly Enlightened
Joined
May 28, 2006
Messages
156
Location
S.Fla
Here in Broward county we use gps for mobile systems and hardwired for firehouse/railroad.Even though the vast majority of our signals are equipped for preempt only a few fire departments have trucks fitted with transceivers.PD and mass transit are not.Emergency vehicles approaching an intersection are not always in the lane for which they wish to proceed.For example sometimes a fire truck will be approaching in the right turn lane because it's clear then make a left at the intersection.So sometime the preempt doesn't work as intended.

As for specific frequencies I highly doubt that information would be online.
 
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