Having a good set of (working) headlights is a crucial feature of any motor vehicle, assuming you want to be able to see the road ahead of you when there’s a lack of sunshine. Headlights are also essential to be noticed by other cars and traffic participants, but if installed improperly they can end up blinding an opposing driver with potentially fatal results. This is a major worry with LED lamps that are increasingly being installed in cars, often replacing the old-style halogen bulbs that have a very different color spectrum and beam patterns, to the dismay of fellow road participants.
This headlight glare can also be simulated in driving simulators, as in a 2019 article by [B.C. Haycock] et al. where the effect is of course diminished because displays can only get so bright. Of note is that it’s not just LED lights themselves, but also taller vehicles and misaligned headlights, all of which makes it important that the angle of your car’s headlights is proper. You want to see the road in front of you, after all, not illuminate every house in the nearest settlement two klicks away.
Compounding the problem is that the shorter wavelength, blue-ish light of LED headlights is more energetic than the more reddish, longer wavelength of halogens and are generally perceived as more intense by our eyes. Ultimately the solution appears to be adaptive driving beam headlights (ADB), a technology that constantly adjusts the headlights to the circumstances. ADB has been common in e.g. Europe already for the past 15 years, and is allowed in Canada since 2018 and in the US since 2022 after a rule change by the NHTSA.
With plenty of improper headlights on vehicles in North America still, it’s best to practice defensive driving, with a brighter dashboard illumination, anti-glare coatings and safety squinting when a miniature solar system passes by during an night-time drive.
A lot of larger SUV’s have auto levelling headlights that adjust the headlight angle if the truck is heavily loaded or towing a heavy trailer. These were most commonly halogen. If anything in that system gets messed up, it can lead to one or both headlights being pointed high.
The NTSB has fairly strict rules about headlight beam ground coverage, which is specified as a pattern on the ground at a known distance ahead of the car, regardless of the car’s size. So in theory even the monster tank trucks that we have now should have their lights shining downwards. However, once the car leaves the factory, aftermarket lift kits and oversized wheels mess that all up. One potential benefit of LED headlights in this is that they’re usually (always, in my experience) an array of individual LED’s, rather than one near-point source like a halogen or an incandescent, so they can be designed to shut off some section of the beam to prevent glare to specific oncoming traffic. (I’ve helped design/build a prototype that does this.) But thus far, nobody seems to want this. They just want brighter lights and more of them.
Living most of my life in Texas, I can confirm that most blaring truck lights are a result of aftermarket lift kits and lax state safety inspections.
It looks like the most common ADB systems are as you describe: steering the beam with projector optics and an LED matrix. These need more LEDs than a traditional high/low beam only LED headlight, and a scanning driver that talks with the ADAS to determine who not to blind, but on the whole not too expensive a solution once it’s popular enough to cost optimize. Again, it’ll take legislation to get beyond a luxury feature in the US.
You have to realize that nearly all drivers approach their vehicle with…
Smelly water goes in this hole.
Floor button makes go.
Hand wheel makes turn.
Oh no. Car no make lights!
$200?
I can buy light for $30 and plug in.
Never thinks about it again.
Or worse.
Oh! This cool off-road light bar would look bitchin’ on my truck.
$80? Score!
No thoughts were given to what it will do to others, or whether or not it’s even legal to put on your car.
As usual, until NHTSA requires manufacturers to add a feature that protects everyone but the car’s owner such as ADB, it will only show up in luxury vehicles to round out a long list of otherwise useless bullet points. Like airbags, ABS, and emissions controls, it needs to be a law for a few years before it makes a difference on the road.
White LEDs have lots of blue (<500nm short wavelength) light but this has very little effect on the perception of brightness because human luminous efficiency isn’t very sensitive to these wavelengths. More likely that the auto LEDs are just pumping out a lot more light.
But we perceive blue light to be brighter, which is the problem.
I don’t get it; the efficiency argument doesn’t really hold water with auto headlights. The extra draw on the alternator is not an issue. Why not just stick with old DOT designs? I’m guessing there are galloping safety regulations for new cars, as is always the case
Power efficiency is only an argument made for electric vehicles without an alternator.
In theory a properly designed LED bulb should offer much better longevity – although that only applies for designs that don’t drive the LEDs at high current, which seems unfortunately rare these days.
Otherwise you’re right, regular ICE or hybrids probably should stick with traditional halogen for the time being through.
That energy comes from somewhere; the alternator isn’t just a magic limitless can of pixie dust. Less power drawn by incandescent bulbs means less power required to turn the alternator.
It’s small, but a bunch of small adds up. My car has a “max efficiency” mode which reduces the power to the seat heaters, reduces the HVAC output, etc. It makes a measurable difference over time.
LED lighting gives auto designers an incredible variety of options for shape, layout etc. that just aren’t possible with old halogen lighting solutions, the colour temperature isn’t affected by voltage variations and they’re much more robust, the laser lighting solutions are also pretty cool.
Let’s not forget those custom headlights gives automakers incredible room for profit along with planned obsolescence.
E.g. $2500 to replace a broken headlight on a General Motors SUV.
An incredible variety of pains in the ass! The expense and complexity of doing a simple job like changing out the lights has gotten entirely out of control, and it’s unconscionable that certain lights have digital features which can end up bricking the whole car if they malfunction and screw up the CAN bus.
I think I would prefer to sacrifice certain crazy shapes of headlights for the sake of the above concerns; plus, auto styling has been absolute dog vomit for decades, so it’s not like the extra freedom for designers is providing any benefit.
Signed,
Old man yells at cloud
I’m sure the old DOT designs were (supposedly) dropped for aerodynamic efficiency (i.e. improved gas mileage).
Factory installed LED headlights usually aren’t a problem. The main issue is when people decide to install LED retrofit kits into headlights intended for halogen bulbs.
This is indeed the problem. And as usual, it’s a cascade of problems. First we had cars designed for halogen bulbs, which as a safety feature added detection of a failed lamp, and depending on the car, took some action if the current through the lamp was much less than expected. This meant that replacement LED lamps had to use nearly the same amount of current as the original halogens. The only practical way to do this was to use far brighter LEDs than necessary. On my car, the action the car took if the lamp didn’t consume enough current was to turn on the high beam as an emergency spare, which compounded the problem by not only being brighter than the original, but by being aimed higher as well.
From my own experience the ADB fitted to cars here in the UK is mostly useless, being unable to cope with anything other than a straight, flat road. A bumpy road or a corner and suddenly you’re staring at a pair of LED neutron stars.
Manufacturers also seem to tune their ADB sensors purely to detect cars. If you’re a pedestrian, cyclist or motorcyclist, well you don’t count. As a motorcyclist who has astigmatism I’ve pretty much given up riding at night, it’s almost impossible to see anything due to the lights from approaching traffic.
The fix isn’t difficult. Forget about worthless tech like ADB, just put in place regulations to require vehicle lights be below a certain colour temperature and emit only a certain amount of their light in the blue spectrum. Make them look as close to halogen lights as possible, in other words.
ADB is total failure, even with newest european car models, is very slow to adapt ( maybe the premium and expensive models work best ). So you get blinded always on first encounter. Korean electric cars are the worst, do they even have that feature. It does not matter if the car behind you or comes towards you. When ADB car is driving behind you on twisty roads, you get blinded thru sidemirrors on turns. Because even if it detects your rear lights, let’s maximize light output by lighting ditches beside roads, even when not needed. And let’s never mention automatic Hi/Lo beam control.
“let’s maximize light output by lighting ditches beside roads, even when not needed.”
So, you don’t drive in urban, suburban, or places with wildlife?
Why engineer something not fit for purpose (LED headlights), then continue by engineering a complex and faulty compatibility layer (ADB) to make them moderately usable, when the original product (incandescent bulbs) worked perfectly? Are the companies involved really that afraid to admit they made a mistake?
As someone with halogen lights in their car right now I can verify that they dont in fact ‘work perfectly’. They function but modern systems when I’ve gotten to use them in a rental or the like are better, brighter, and illuminate at a greater distance than anything my halogens ever did. That and the fact that I have to replace the dang things on the regular makes them unfit for purpose comparatively.
All we need is for aftermarket reflector designs to be made for all older models of car at an affordable price. Then everyone in my situation could upgrade without causing disruption to others the way just throwing LEDs in as is does.
Better for YOU (in your opinion) and worse for everyone around you, IS worse.
How many actual studies on headlights, or road lighting in general have you read?
Headlights/road lights should be JUST bright enough for object recognition.
Brighter lights FEEL safer, but are not, and cause real problems for everyone, including the driver.
As someone with halogen lights in their car right now I can verify that they dont in fact ‘work perfectly’. They function but modern systems when I’ve gotten to use them in a rental or the like are better, brighter, and illuminate at a greater distance than anything my halogens ever did. That and the fact that I have to replace the dang things on the regular makes them unfit for purpose comparatively.
All we need is for aftermarket reflector designs to be made for all older models of car at an affordable price. Then everyone in my situation could upgrade without causing disruption to others the way just throwing LEDs in as is does.
Another victim of the HaD Double Post “feature”! You’d think they’d come up with a hack to fix that or is it all bravado and blowing smoke?
Have you ever considered that brighter lights illuminating at greater distances are exactly what’s blinding the oncoming traffic?
But if I’ve got brighter lights, I can see the idiot driving into me head on like he’s blind…
…oh, whoops.
It’s not that simple – the shape of the beam is important. Modern headlights (when correctly aimed) put more light on the ground with less light in the eyes of oncoming drivers.
The drawback is that when they’re not properly aimed, the “more” that should go on the ground ends up going into the eyes of oncoming drivers.
This seems to be compounded by drivers who are unable to figure out why they’re getting flashes of high beams everywhere they go.
Throwing more light isn’t inherently a good thing – the eye takes time to adapt so when you have miniature suns blasting out of your car to bounce back at you and are being dazzled by the intense blast from everyone else’s you are more blind in the dark than you would be with everyone using more modest illumination – seriously sit outside away from any unexpected lights for a while and on most nights you’ll be able to see pretty well just in the moon light, at least until you turn your phone/torch on and ruin the night vision, at which point you’ll be virtually blind.
Of course now the arms race for brighter and brighter spotlights that will render you blind to everything in gloom and dazzle everyone else is already in progress…
Brightness and intensity are not the same. For instance, you can comfortably look directly at a traditional 40W tungsten light bulb for an extended period because its light is distributed over a broad area. In contrast, a milliwatt laser can cause blindness due to its concentrated light. The same principle applies to car headlights. Older cars had large headlights that emitted light evenly over a wide area, whereas modern LED headlights are highly intense pinpoints of light that can be painful to look at. Instead of blaming the technology, the issue lies with prioritizing aesthetics over practicality and the shrinking size of the emission aperture in modern headlights.
“Ultimately the solution appears to be adaptive driving beam headlights (ADB), a technology that constantly adjusts the headlights to the circumstances.”
FFS, why change a thing that already works? The solution is not always more tech..
Or we could have corner cubes as standard equipment for car grills and provide “feedback” to oncoming drivers on the effectiveness of their LED headlights.
“I suggest a full frontal assault with automated laser monkeys, scalpel mines and acid.” – Strax
You joke but there are laser headlights.
https://youtu.be/lVtnH0KscS4
You joke but there are laser headlights.
https://youtu.be/lVtnH0KscS4
You joke but there are laser headlights.
https://youtu.be/lVtnH0KscS4
You joke but there are laser headlights.
You joke but are there laser headlights?
Gin juke mutt mare are graser bed fights.
https://youtu.be/PwpD3USKEKw
LED much better for me. I have foheen reisch and am blinded by the red light halogens or incandescents put out. Also causes intense burning eye pain and 10 to 15 seconds of almost complete blindness. I used to have to wear dark red blocking sunglasses to drive at night or be in building with incandescent lights. Would turn headlights off when alone on road as could see better by moonlight or even starlight. About 20 years ago I installed a pair of $3500 at the time HID lights on car, now can leave on when alone on dark road. Since then have upgraded to LED on same car. With many adopting LED, I rarely have to wear sunglasses at night, normally just close eyes for a few seconds when car with incandescents approaching.
And I have to do it for these LEDs, lasers and bad HIDs. I think we should go night vision goggles for all and quit the light pollution.
I remember fondly doing 190 mph on a deserted highway in a friend’s 1980s corvette headlights off while wearing Vietnam-era night vision goggles. Few moments of waking life have been as thrilling as that.
Try it in a helicopter!
“normally just close eyes for a few seconds when car with incandescents approaching.”
You’re describing someone who should not be driving ever.
From my experience there is another problem. Whenever i ask mom or friends or other people about beam height switch, they don’t know what l’m talking about.
So i think that problem is not only too much trust in automatic systems, but also some kind of lack of knowledge how lights should work like.
How’s your experience with friends?
If I asked a hundred people, friends or strangers, 90% would have no idea what adjusting the beam height means.
Beyond the basic minimum driving controls, nobody cares.
I need to know what every button or function is on every everything I own. Always. And then I need to figure out the most efficient way to use it, least presses, smallest hand movements, shortest time.
I suspect I’m a bit of an exception.
An outlier.
Displays can only get so bright and this a discussion of night driving? Displays should not even be in a car at any time visible to the driver, this is common sense and is an even bigger problem than headlights used only at night. There was a standard for in dash info, 8 characters in several seconds. Eye focus needs to be at distance all the time without in-dash distractions.
I rode in someones car at night with a tablet sized aftermarket “radio” glaring blue light with no way to dim it when headlights are on vs. day. Looking out of that car I was blinded, but he thought it was OK. I’ve seen disco lights blinking in the inside of cars.
Could some standard up to date unit light be integrated into all cars and trucks like sealed beams were for so long? These things can be smaller than old sealed beams. That way camera or cop almost anything else would be tagged and the rest of us can get back to driving. The current way is unenforceable.
So no speedometer no fuel guage and no check engine light. Gotcha.
So, what is really at the core is that we have better regulation.
“Better? Or worse?”
We certainly have more of it. I loved your work in Half-Life 2 btw
One of the biggest problems come from misadjusted headlights. When you buy a new car the steering is NOT aligned and the headlights are NOT adjusted. the factory puts them “in the aproximate” range of good. If you don’t believe me do a search for an alignment rack in a manufacturing facility. The headlights should be pointed slightly down and to the right (USA) so you don’t blind drivers. I drive a 2005 Jeep Wrangler with sealed beam headlights. My headlights have to be adjusted with each bulb replacement. My headlights converge about 100 feet in front and on the fog line (passenger side white street marking). Use your favorite search engine to look up your specific aiming procedure. https://www.popularmechanics.com/cars/a257/how-to-adjust-lights/
I fully concur however that some aftermarket bulbs are horrendous. Our mail service just replaced the light on the older mail trucks with the intensity of white hot sun that you can’t even look towards when they are approaching.
There is nothing stopping manufacturers from installing LED headlights with a lower color temperature.
Surely LED lamps with improper beam patterns are illegal?
If I tried that I’d just changed to replace them with something legal.
Tip of the hat to the artist. I feed bad for that car as it experiences the trauma of its mutant power manifesting for the first time.
Anyone want to pool our funds to pay to have a Cyclops-style ruby visor drawn on the poor thing?
The biggest issue with after market LED bulbs is that the actual source of the light, which used to essentially a point source, is now larger and a different shape – typically longer and protruding more in the front and rear directions. This means a reflector for a halogen or incandescent bulb is no longer reflecting the light properly because the source of the light isn’t in the same spot. The light is effectively “out of focus” and throwing light where it was not intended to go.
It’s not just lumens, is the direction those lumens are put to work.
This! Reflectors made for halogen bulbs are designed to reflect light from a very precise location within a bulb… which is exactly where the original filament would be. There are no LED bulbs that accurately place an LED in this location. Indeed, it’s quite impossible since at best, there are two LEDs installed back-to-back and separated by a strip of metal meant to pull heat from the back of the LEDs. Therefore, a perfect focus can never be achieved. This is why attempting to recreate a sharp cut-off in a headlight designed for a halogen bulb results a blurry mess with even the best LED replacements.
♪♫♪ Uuuuuh blinded by the (led) lights ♪♫♪
If I recall, don’t train engineers dim their lights when passing another train?
I don’t drive, but even as a pedestrian, having twin supernova burn your retinas out of your skull
while you’re trying to cross a street in addition to the having the bright white street lights shining
down from above turning everything in their path a stark white-gray along with people who wear dark
clothing at night that decide to cross in front of your car just as the light turns green.
Lighting up every square centimeter of a city isn’t the answer. Having headlights that can light up Mars
from New York City isn’t the answer. People are already having trouble seeing in the dark as their night
vision is being affected by these streetlights, headlights, computers, phones, tablets……
I think and this is my own opinion, that there will be a time when someone born today will never be
able to have the night vision that people in the 1970’s had. Also, in Australia, aren’t the lines on the
road painted with fluorescent paint so they glow under UV light? More light isn’t the answer.
People are wearing sunglasses at night because these new LED lights are brighter than Betelgeuse.
I see cars on the road all the time with one headlight out. They’ll pass a cop and the cop does nothing.
Then you see the ads for “Battle Vision” anti-glare glasses for driving at night.
Even some bike lights are ridiculously bright. So we have all these technologies emitting ‘blue’ light
and they sell sunglasses to eliminate the ‘blue’ light. I’m so glad I rarely go out at night anymore.
One of my EE professors espoused the idea that all vehicles should have polarized headlights and windshield glass. If, for example, everyone’s lights and windshields were polarized at 45 degrees upward and to the right, you would see light from your vehicle (and others traveling in your same direction) strongly, but your windshield would attenuate the headlight beams of oncoming vehicles because they’d be at cross polarization.
What could go wrong?
That’s an interesting idea. But that still wouldn’t solve the problem of pedestrians, unless the pedestrian wears polarized glasses as well.
One of my EE professors espoused the idea that all vehicles should have polarized headlights and windshield glass. If, for example, everyone’s lights and windshields were polarized at 45 degrees upward and to the right, you would see light from your vehicle (and others traveling in your same direction) strongly, but your windshield would attenuate the headlight beams of oncoming vehicles because they’d be at cross polarization.
What could go wrong?