You know what’s not a lot of fun? Getting rear-ended while driving. In fact, we dislike this form of human interaction so much that in 1986, a law was passed that mandated a third, high-mounted brake light (called a Center High-Mount Stop Lamp, or CHMSL), something that had been proven to be effective since 1974, when formal tests were first undertaken. The light works; a 2014 report from, of all places, the American Psychological Association notes that since the adoption of third brake lamps, “there have been about 200,000 fewer crashes, 60,000 fewer injuries, and more than $600 million in property damage saved every year,” which is no joke.
CHMSLs are as much a part of the fabric of our lives now as such lesser elements as the nuclear family and the aching beauty of a sunset. But could the CHMSL somehow be improved? And, if so, could it be improved by combining it with a rear windshield wiper? I’m happy to tell you. that I do believe this is possible. Let me show you.
The concept is wildly simple: on vehicles that include a rear-window wiper – which, thanks to the prevalence of SUVs and crossovers is a very significant portion of the automotive landscape – there exists an opportunity to mount the mandated third brake lamp right onto, or integrated into, the rear wiper arm, thusly:
Looks good, right? Of course it does. Now, once we combine the CHMSL and wiper, bold new worlds of wiping and CHMSL-ing open up. Well, really, two things open up, perhaps three. First, the wiper mount means that the CHMSL is now able to move, in an arc, like a rainbow or a roach crawling on the Arc de Triomphe. This means that we can place the CHMSL in other positions along that arc, say vertically, as a higher-visibility position in conditions where more attention is desired for a driver’s braking:
Also, in emergency braking situations, the CHMSL can wave back and forth, boldly (visually) shrieking its warning, a very eye-grabbing and attention-seizing display that should awaken even the least attentive of drivers:
Plus, in rainy weather, when visibility is already impaired, the wiper and CHMSL will already be in motion, helping to make each and every braking event obvious and safe, even in the most brutal of thunderstorms.
Tell me this isn’t a good idea! Why hasn’t any bold and safety-focused carmaker attempted this yet? We have the technology, all we have lacked is the will. Perhaps that will now change.
CHMSLs belong on wipers!
I can hear the animated image, that wiper is dragging across dry glass etching tiny scratches into it with each press of the brake pedal……
It makes my skin crawl…
Looking forward to tomorrow’s article where you propose having a semaphore pop out of the moving light wiper while making a loud “ding” sound.
Being from a state with winter, I say the center brake light should always be inside the rear window within the swept area of the rear wiper, and within the rear defrost area. I’ve gone on several road trips through WI and MN during snow storms where the entire back of the car will get covered with snow that needs to be constantly removed.
It’s not a good idea. A brake light mounted at the top of the rear windscreen is ideal. It’s not waving around and causing a distraction. Many cars don’t have a rear wiper. Some people like to delete their rear wiper if they have one. High stop lights these days are usually integrated into the car such that it’s either not worth the effort to remove, or doesn’t cause enough “aesthetic distress” that people want to get rid of them.
I have always been a fan of having progressive brake lights. A 3-segmented brake light that would illuminate sections based on how hard you are braking e.g. one section lit for a gentle brake tap up to all three lit for a full on panic stop.
Nerdy fact. In Spain, the third brake light not only wasn’t required, it was banned all the way through the late 90s. Most cars would come from factory with just a weird protuberance were the light was supposed to go.
The law said two brake lights in the back, and it was easier to remove parts from new cars than to change the law.
More movable parts means more thing that will break or wear out. But looks fun!
Bad idea because smart-ass people would put an image of a clenched fist in their back window, and when the wiperlight was in the up position … well you get my drift.
If it wipes and the LED refreshes fast enough you can even make it display messages and pictures!
Give it enough colors and you have a TV on your rear window.
Even in monochrome red, I would just want to send text messages to drivers behind me.
Feels like a solution without a problem, since CHMSLs are pretty smoothly integraged nowadays. Given how many of us here have voiced their irritation with the rear turn signals located on the bumper in a number of new cars, I think this is going to be a pretty disliked idea.
This throws off the symmetry and any visual balance between the 3 stop lights, and having the thin CHMSL wave like an aircraft marshaller seems like it will make it more distracting, possibly more difficult to judge what is actually happening.
Also echoing everyone else that has voiced their dislike of the flashing CHMSLs dealers will tack on.
I don’t care if it is a good idea or a bad idea, I like your ideas.
Oh, no no no. Not a good idea. The overflow red reflection against the rear window while moving back and forth would be wildly distracting.
This is not a good idea.
Not sure why, but my brain has been wired to call this object the CMSL, or Center Mount Stop Light. For… years now. I’ve even “schooled” people with my infinite automotive knowledge about said CMSL.
The H is redundant. Can we drop it to support my ongoing ego that knows it is wrong?
Well the law stipulated it had to be above the center of the standard brake lights, so High isn’t necessarily redundant.
I can use brake (or tail) lights of a vehicle in the distance to judge its position in the road/lane at night. That’s only possible when the lights are fixed and not moving. I know the outer brake lights would be fixed but seeing the center light move back and forth certainly makes it a bit confusing. Not having the center light being in the actual centerline of the vehicle definitely doesn’t help with this either.
I’m not sure I want the nails on a chalkboard sound of a wiper going across a dry window when I hit the brakes.
I have always thought brake lights should not be activated by the brake pedal, but by an algorithm using multiple inputs. Just because someone is using their brakes for a bit to maintain speed down a hill or tapped their brakes briefly to disable cruise control shouldn’t cause panic braking by everyone behind them.
Brake lights should light up based on deceleration and speed regardless of brake pedal activation. Deceleration could happen from a downshift, an incline without adequate throttle, or many other things. At a stop, the brake lights would also be on.
The other thing I think all cars should have for the CHMSL is 5 distinct separated lights in a row, that light up based on how hard the deceleration is. A mild deceleration would light up the middle CHMSL light, a medium deceleration would light up the middle light and light to each side of it, and a hard deceleration would light up all 5. The lights would always light up in a sequential pattern, middle outward (to show your car has this feature), even if you went from cruising to panic braking. And at a stop, all 5 would illuminate.
I hate that my wife’s CX-9 applies the brakes and brake lights when using cruise control downhill. It applies the brakes way more than I would and makes me look like a nervous driver.
I think my Toyota Hybrid does this. I have noticed that under very light braking (REGEN) the brake lights do NOT come on. If I just tap the pedal to disable cruise they do do come on. Maybe a position sensor on the pedal?
Counterpoint: I don’t like cars that have rear wipers.
KISS. I’ve dealt with waaaaay too many electrical gremlins and dead batteries in my relatively short life to want anything more in a car that requires electricity than what is legally required. No speakers, no radio, no electric seats, no electric windows, no electric mirrors, no seat heaters, no electric fans (climate control or otherwise), no infotainment, no dome lights, no rear wipers, etc.
I’m just about ready to just bike everywhere FFS!
Depends on the vehicle. Some of these things manage to splash everything onto the rear window. Maybe a redesign to avoid that is better than a wiper, but it’s nice to have one. Pain when things go wrong, sure, but sometimes a good thing.
That said, you and I have a very different view of electrical items. Please give me climate fans and AC, electric mirror adjustments, and speakers. Electric windows at least in any four door. I’m okay without seat heat or electric seats and don’t really need a dome light, either.
But, yes, biking is good!
Yeah, I’m more of the opinion that what the rear wiper solves is usually already solved with proper design.
With proper design you don’t need climate fans. Just vents and proper ram air intake. Land Rover got it right with their Defenders, you open the vents and you can see daylight through them. Sure it doesn’t do much when your at a stop but for me I just roll down my windows, or if you want cooling air but it’s smokey outside so you can’t use ram air, but that happens so little to me it’s of little consequence and I don’t mind the smoke really. However modern cars seem to have no natural ventilation short of rolling ones windows down and for most 4 door cars the buffeting from just having the front windows down is so extreme you have to roll down the rear windows as well which is bad design IMHO.
I’m probably going to get a late year 2CV and a little putt putt motorcycle with a kick starter and just say F it. The spicy magic that is electricity is useful when it works, but batteries leave a lot to be desired.
I drive very little since I switched to WFH (<8k/yr), but every single time I go somewhere I spot at least one car with one or more brake lights not functioning.
Although I will grant that there are probably a lot of drivers who don't give a rip, I think the more common scenario is that they don't know. AFAIK, there is no requirement for the car to warn the driver that they have a dead brake light, and it's usually a two-person task to check them manually. Hence I would imagine most people don't regularly check their brake lights.
My 1987 BMW had a warning light, so I know the technology has been out there for a while. But I'm pretty sure most manufacturers don't implement a warning. I think it's crazy that manufacturers are allowed to skimp on such an important safety warning device.
Let's fix this problem before we mess with the CHMSL (or at the same time would also work for me).
“…called a Center High-Mount Stop Lamp, or CHMSL…”
There’s no reason to stop (so to speak) at merely calling it that:
https://live.staticflickr.com/65535/52472774190_d011b247fc_c.jpg
If you’re going to do this you might as well put amber lights on the windshield wipers. Visibility is visibility, right?
It’s not a good idea. (Hey, you asked.)
Placing the CHMSL at the top of the rear window already accomplishes the goal of the high-vis position, and without having the rear wiper looking like a middle finger in the window.
But you know what would make the CHMSL even more effective? Making it flash. This is already an option for motorcycles, and with an LED high-mount light the control portion would be trivial to implement.
Bad weather? Use the “slow-flash” mode.
Heavy fog? Use the “rapid flash” mode.
Emergency braking? Use the “dance party” mode. Tie this to brake pedal pressure: driver standing on the brakes HARD = emergency.
We have the technology! 🙂
Note that the human eye is better at recognising change over time than instantaneous change, so having it pulsate would be better than straight flashing, if you want to grab attention.
Yeah, some of the newer cop cars around where I live are kitted out with the flashing brakes, and it’s not something I’d want in widespread use. I’m about as desensitized to strobe lights as a person can be from working in photography and concert videography, and the effect of the flashy brake lights on me is still far more disorienting than attention-grabbing, especially if they pop off close by in an adjacent lane.
You’d think cops of all people should know this, since disorientation is the exact purpose of the strobe function on their pistol lights.
the aftermarket “flashing” “california brake lights” on my motorcycle are technically “modulating” rather than “flashing” – they vary i intensity from ~20-100% (modulating) vs 0-100% (flashing).
FMVSS 108 defines modulation with respect to motorcycle headlights.
further, skene design (i am a customer) incorporates a “conspicuity flicker” into their lighting products – approx 40Hz modulation that is obvious when seen obliquely, but almost invisible viewed straight on.
Fair enough – we can substitute the verb that makes the most sense: modulating, pulsing, etc. We seem to agree that using something other than a plain on/off light would be helpful, so we can go from there and solve this problem for the auto industry. 🙂
Shhh!
Attention whores are annoying enough as it is! Don’t give them any more ideas.
Oh I can’t stand the pulsating CHMSL. We have some car dealers around here who put them in every new vehicle they sell and it’s annoying. It’s the new pinstriping scam.
Same. I think an emergency function as described, kind of like the secondary emergency lights as in some German vehicles, could have a place. But not the cheapo part that dealers tack on, in regular day to day driving.
If it isn’t already mandated that the CHMSL be places as high as possible on the rear of the vehicle, it should be. My MINI Coupe, already a small, low car compared to a lot of other cars out there, has its CHMSL just a few inches above the top of the main brake lights, and below the bottom of the rear glass. I’ve always thought it would be much more visible if it were at the top of the glass, like most other MINIs.
https://file.kelleybluebookimages.com/kbb/base/evox/StJ/9493/2014-MINI-Coupe-rear-angle_9493_173_640x480.jpg
You should patent your ideas, Torch.
I like the idea, but I see some hair on it:
tl;dr
Terrible idea.
Why stop there? With LED technology, we could change the color of the CHMSL based on the situation:
Red would be a full panic stop.
Orange, maybe a 50% panic stop.
Yellow might be 10%.
Blue would mean “Hey, nice car!”
Also, why not have the CHMSL be the full perimeter of the rear window? the possibilities are endless!
Oh god, aren’t the blinking ones bad enough? You want to distract me from the rest of traffic even more by making them move?
The blinking ones are illegal federally, but the way they get around it is by pulsating them. In other words, they don’t actually go completely off. I find them very annoying.