Probably a dumb question, but this topic came up in my car pool recently. Cops had pulled someone over a distance ahead, and none of us could figure out where the pull-over had occurred. We were to make a right turn at an upcoming intersection, and the driver didn’t know if he needed to slow down/change lanes as we approached it. Where was the pull-over? Was it in our lane? We creeped up the road, and only when we got near the intersection did we figure out that the pull-over was much farther ahead (mostly by seeing cross-traffic at the light blocking the cop’s lights).
We never had this issue when cops had incandescent lights; in the old days, with good vision, one could say “oh, he’s a couple of lights up, we can make this turn.” There’s something clearly related to the frequency or polarization at which LEDs emit light that affects depth perception. What is it? Why can we not easily determine the distance of these LED emergency lights?
And they need lenses or reflectors to make that cone spread out wider, in a “floodier” configuration. Maybe the LED cop lights purposely changed the optics to make them visible from further away.
When I was a truck driver I often had this problem. Driving on a dual carriageway at night with no street lights and I see blue strobes ahead. Naturally I slow down, but as I get nearer I am totally dazzled and slow down to a walking pace - nervous that I will be hit from behind.
When I get to the scene, I find that the cops, and whoever they are talking to are completely off the road in a layby.
I also have a problem with - why do the four cop cars, two ambulances and three fire and rescue vehicles attending an accident, need their light bars fully lit up?
In part, the problem is going to be exacerbated by the way the LED lights are driven - police light bars typically emit very brief, very intense pulses from any given lighting element - this makes it very hard for your eyes to triangulate and focus on them. For the same reason, lightning bolts typically look thicker than they really are - because they are so brief and bright that you are almost guaranteed to see them out of focus,
In the case of emergency vehicle lights, it also doesn’t help that they are so intense that they cast noticeable flickering, changing illumination upon on all the surrounding objects and scenery.
It is often mentioned in training and safety to turn down/off some emergency lights and more often overturned by the driver or even the incident commander on site of the scene.
The thought process goes something like, yes we know we are blinding and disorientating the driver, but how can they hit a truck with that many lights flashing. And the fear that if they do hit the truck the question will be did you have the emergency light on, and do not want to answer no.
This is for the fire service, for cops I suspect the answer is more like because we can and you can’t, just a visual reminder of their power to park were they please blocking lanes and blocking traffic, even blocking emergency vehicles, and to display those lights. Sort of a visual to reinforce their authority.
The human eye doesn’t focus well on the blue wavelength. That’s why “blue blocker” sunglasses make things sharper in appearance. cite:
Another interesting factor is that the eye has a hard job focusing all three colours at the same time. Focusing is particularly difficult with blue-violet and this results in the haze effect caused by blue-violet light which can lead to headaches.
So basically at night the bright blue lights used on police cars is about the worst thing possible in terms of blinding people and making it hard to focus on. They should have stuck with red. “back in the day” of the single red bubble gum light it was easy to see and judge distance.
it’s also why fog lights on cars used to be yellow, and part of the reason France used to require yellow headlamps until the '90s. Also why some teams who do endurance/nighttime racing (like the 24 Hours of LeMans) use yellow lights.
but try telling that to these idiot kids who put intense blue HIDs in their cars and insist “no dude, I can totally see better!”
And fundamentally the police WANT for their flashers to be seen far and wide and for everyone as far as the horizon in every direction to slow down and prepare to be stopped.
Heck, around here the common practice is for the police just doing their regular rounds at night to keep the flashbar lit up anyway so that the entire neighborhood knows they’re somewhere in the next four blocks in some direction or other, and anyone who may be hanging out up to no good scrams or at least gets squared away, thus saving them the hassle of having to stop and ask what are you up to.
Probably just what you alluded to before – they’re afraid of being hit from behind when they are stopped near or even on the road.
Youtube has lots of videos of some person (usually a drunk) plowing into emergency vehicles despite all their flashing lights.
When our local PD started using these I almost hit an officer with my car at the scene of an accident. He was on foot next to his cruiser, but the lights were so bright that it was near impossible to see the dark shape of the officer until I was right there. I don’t think he realized how close I was, since he didn’t budge.
Fortunately for both of us I was driving very slowly while navigating around the accident and nothing happened. It scared the snot out of me and I wanted to go to the police station the next day and see if I could find a sergeant and give them a polite word of advice about how invisible they become at night next to those lights—I never did. I wonder if emergency personnel are told anything about this in their training.
They’re told to blind people at night? Well bless their hearts.
I just came across a cruiser doing “construction duty” last night. He was parked at the beginning of the construction where only cones separated people and equipment from traffic. Couldn’t see shit. I finally blocked the lights with my hand so I could see the single lane I was suppose to be in.
This would obviously be true for the vehicle(s) at the rear, but that big red F&R tender with fluorescent yellow bands at the actual scene doesn’t need them at all. Apart from that, it must be pretty horrible for any victims being treated or cut out of their cars, and distracting for the various crews helping out.
All those flashing illuminations also cause the drivers on the other carriageway to slow down and look - even to get their cameras out to take pictures - this soon causes a secondary rear end collision in the other direction.
I’ve been bothered by this for a while. Around here the DOT plow trucks are using these now. I drive in the dark every morning on curvy mountain roads. Lots of snow. The plow trucks warning lights are positively blinding.
