But highly susceptible to unauthorized use. The app version can also alert drivers directly with an audible alert that an emergency vehicle is close by
Long ago I used to read i-hacked.com with great interest. They had an article about a DIY "MIRT" which produced the right infrared signal to trigger these:
Of course this article came with many disclaimers that to actually do this would be very illegal.
I was more than a little sad when I typed i-hacked.com into the browser and got redirected to some etsy page. Thank goodness for the Wayback Machine, I guess.
Or by doing even a slight amount of encoding of the IR signal. Transmitting a single byte as a key (set by region, same as fire dept. elevator keys) would be enough to prevent people from using their TV remote controls or whatever to trip the preempt sensors.
That being said, this is kind of a non-issue already, I have heard a story about someone abusing the preempt sensors like 10 years ago and never since then. Maybe there already exists an encoding scheme.
Anecdotal of course, but in my 20 years of driving I've never once seen a vehicle activate the red light override sensors that wasn't obviously a legitimate emergency vehicle.
IMO a huge majority of people realize how illegal it would be to mess with these things, and the risk/reward is very low. Anyone who would take that risk would probably just run a red light instead.
Not really a real problem that actually happens, but you could fix it by only making it work with visible light pulses. Sure, people still might use it illegally, but you couldn’t be very subtle about it.
