Part 1: Lighting the Way with Guest Daniel Stern

Daniel Stern is an expert vehicle lighting consultant based in Vancouver, British Columbia, and Seattle.

Part 1: Lighting the Way with Guest Daniel Stern

Ever wonder about those cool LEDs and other lighting systems appearing on every new vehicle now? Or have questions about glare, aim, high beams, fog lights, and upcoming headlight technology? This week and next, I’m pleased to feature a true vehicle lighting geek—Daniel Stern.

Daniel is an expert vehicle lighting consultant based in Vancouver, British Columbia, and Seattle. He serves as an expert witness, actively participates in technical standards development and research bodies, has contributed text to regulations in several countries and territories, and has attended the United Nations vehicle lighting regulation working group at the invitation of its president. He collects technically and historically significant car lamps, helps drivers safely upgrade their cars’ lighting, and serves as Chief Editor of the industry’s technical journal, DrivingVisionNews.


ML: What do you actually do?

DS: I am a vehicle lighting expert. I write, speak, educate, and inform all kinds of audiences about the technical, technological, and regulatory aspects; the performance and safety aspects; their design, styling, engineering, and construction; and their history and future…really everything about car lights and how we interact with them.

Part 1: Lighting the Way with Guest Daniel Stern

ML: How did you get interested in vehicle lighting? After all, most kids don’t think, “When I grow up, I want to be a car headlight specialist.”

DS: That’s almost certainly true! I come about as close as can be, though; when I was around 7, my father was driving me after dark. He showed me how the car had low beams for when other drivers were on the road in front of us and high beams for when the road was empty. His Oldsmobile had four headlamps, so that made obvious sense to me: one low beam and one high beam on each side. Then I went to summer camp and my counselor had a VW Beetle with only one headlamp on each side. The idea of two filaments in one headlamp didn’t occur to me, and I followed the poor guy around all summer asking pesky questions about his headlamps. “Yes, Daniel, my car has low and high beam! Now, will you please go ride horses or do pottery or something?”

Years later I was in dark, rainy, and poorly signed Oregon, and it struck me I ought to be able to see better at night, even in my old Valiant. Around that time, I made my first visit to Europe and noticed many differences in car lights over there. Later, I found myself at the University of Michigan Transportation Research Institute (UMTRI)—one of the world’s foremost traffic, vehicle, and driver safety research outfits. I spent hours in its library reading many years’ worth of science about car lights. I contacted the researchers and engineers who authored these academic papers and asked them questions about their work and their findings. Most were surprisingly patient with me. Nobody offered a course in vehicle lighting, so I had to learn about it on my own.

And now here I am, a vehicle lighting consultant and chief editor of the global vehicle lighting and driver assistance industry’s technical journal, DrivingVisionNews.

ML: Vehicle lighting seems to be developing at light speed (excuse the pun) in recent years. What changes are happening in the industry?

DS: Well, the main thing is the light-emitting diode (LED) revolution. LEDs first appeared on passenger cars as little low-brightness dashboard indicator lights. Its first exterior application was the central third brake light in the mid-late 1980s with a row or cluster of those same low-power LEDs. Now we’ve got all kinds of high-power LEDs that have freed engineers, designers, and stylists from the constraints of filament bulbs and low-power LEDs.

As a result, we’re seeing long thin-line designs, 3D-effect designs, and other neat new stuff we couldn’t do with traditional light sources. And it’s not just for signal lights, either—white LEDs and even laser diodes are enabling radical new headlamp designs that are smaller and slimmer than ever before.

Audi LED Headlight

A lot of technical and technological progress is encapsulated from yesterday’s simple boxes with bulbs inside to today’s highly styled LEDs. But that doesn’t always translate to safety—how good a job they do of their see-and-be-seen life-safety functions. Automotive regulations allow a huge performance range in every exterior vehicle light. As high-tech lighting becomes practical and affordable, ever higher performance is possible. But when regulations are updated (which happens very rarely), it’s usually to allow higher performance at the top of the range—to raise the ceiling—and almost never to raise the floor by requiring higher performance at the bottom of the range.

So, today’s best lights give better safety performance than the best lights of ten or twenty years ago, but today’s worst lights are no better than those of the past. Considering all the vehicles on the road, the spread of lighting safety performance is wider than ever before. For example, the last time the low-beam-headlamp ceiling was raised in the American regs was in 1997, but the last time the floor was raised was in 1977.

High-tech car lights usually cost more, so automakers sometimes prioritize a high-tech appearance over good performance. Consider two examples: In 2014, a Japanese automaker’s very popular small sedan was the first high-volume, mass-market car to feature LED low beams as standard equipment—very high-performing ones that put a remarkably large amount of usable light on the road. But an all-new 2019 version of a German automaker’s popular family sedan now comes with LED low beams that output as much light as headlamps that were state of the art in the mid-1970s! Both of those cars’ lamps are equally legal, and both present a modern, high-tech look. But most buyers won’t discern between them, and they might count the new car’s LEDs as a plus even though some old-tech halogen lamps outperform them.

It’s the same story at the back of the car: The current trend is toward brake lights and turn indicators as small and slim as can be. It’s easy for small signal lights to be either too dim to be clearly visible on a sunny day or so bright that they’re very glaring and uncomfortable to look at—neither of which is good for safety.

ML: Newer vehicles often seem to feature headlights that blind and fixate us with their hues and brightness (especially SUVs). Is this truly an issue?

DD: Yes, this is real; it’s not your imagination. A smaller lamp putting out light of a given intensity looks brighter and more glaring than a larger lamp that’s putting out the same intensity. Headlamps are shrinking ever-smaller while LEDs are evolving to produce more light, so there’s more glare. And high-quality research has shown that bluer white light produces significantly more irritating glare than less-blue white light of the same intensity.

If headlamps were built with warmer-white LEDs, they’d be giving drivers badly needed extra “seeing” light without increasing painful glare. But auto marketers strongly prefer ever-bluer headlamps, insisting they’re closer to natural daylight, which they aren’t in any real sense. And they use the color difference to entice buyers to spend more money so others will feel the need to keep up with the Joneses. So, we have needlessly high levels of glare, and I don’t foresee that changing.

Xenon Car Headlight

There are other contributing factors. In North America, we don’t pay good attention to headlamp aim, which is the single biggest determinant of how well we can see at night and how glaring our headlamps are. There’s no legal requirement for high-mounted headlamps to be aimed lower than low-mounted headlamps—or for headlamps on new vehicles to be aimed correctly at all. Federal regulations are silent on the matter—it’s left up to the states to set and enforce those rules. Most states don’t bother, and those that do tend to have poorly written rules that give a pass to badly misaimed lamps.

It’s also very easy to buy so-called “HID kits” and “LED bulbs” for halogen headlamps and fog lamps, even though they’re unsafe and illegal. Most drivers don’t realize the sheer complexity of headlight beams in terms of the right amounts of light that must be directed toward certain angles for the best visibility and yet away from others so you don’t dazzle other drivers. Unlike your house lights, headlamps—even simple ones—are optical instruments that work effectively, safely, and legally only with the right kind of light source in them. With LED bulbs and HID kits installed, halogen headlamps become dangerous glare monsters that also don’t light your way safely. But they have that bright blue-white glint, and that’s all some people care about.

ML: I’ve been hearing about the high-intensity lighting available in Europe but not here in the US. Is it because of outdated NHTSA regulations? Is any progress being made so we can get that better vehicle lighting here?

DS: You’re asking about Adaptive Driving Beam (ADB), also called Glare-Free High Beam. It’s a camera-driven system that runs powerful high-beam light distribution, tracks the positions of other traffic participants (including leading and oncoming drivers and pedestrians)—and dynamically shadows them out of the beam. This equips drivers with high-beam seeing while exposing others only to low-beam glare. ADB gives the driver an additional 100 feet of seeing distance over low beam—an enormous safety benefit, especially for pedestrians (far too many of whom are hit and killed by cars at night).

Don’t confuse these, however, with “adaptive” lights; ADB is a big advance over the relatively primitive adaptive headlamps that just direct their beam to follow road curves as you steer. Canada is one of the latest countries to allow ADB systems conforming to the international-consensus UN regulations—a notable development, since Canadian regulations are usually kept in lockstep with US rules. The evidence keeps getting stronger that ADB provides a big safety benefit, and Canada grew tired of waiting for US regulators to make up their minds.

YouTube video courtesy of Toyota.

Most automakers have offered ADB-equipped cars in Europe and around the world for some years now, but it’s not yet legal in the United States. News stories in the popular press and auto enthusiast magazines tend to blame stupid ol’, backward ol’, outdated ol’ NHTSA, but the reality is much more complex. NHTSA’s main concern is safety. It needs to make sure automakers don’t put features or equipment into cars that could endanger drivers, passengers, and other people on the road. And it’s been interested in ADB for quite a while but it’s reluctant to sign on.

For one thing, the American legal and regulatory system is structurally incompatible with the UN regulations used by most of the rest of the world. To address that, a Society of Automotive Engineers task force set to work diligently translating the UN regulations’ technical requirements for compatibility with the American system without reinventing the wheel (or the headlamp). But that wasn’t the only obstacle; during a 2015 study of ADB on European cars, NHTSA found some issues. Some ADB systems tested caused higher-than-low-beam glare in certain curved-road and intersection situations that might be peculiar to North American roadway geometry and traffic layout.

In the meantime, ADB systems have been developing by leaps and bounds, and not just in Europe and Asia; even homegrown American suppliers have been hard at work developing them so they’re ready to go when US regulators give the go-ahead. That might even happen in the foreseeable future; recently NHTSA issued a statement that it’s currently working on rulemaking that would amend the regulations to permit ADB.

That’s encouraging, but the current US Presidential administration has a strong antiregulation attitude—even though regulations don’t necessarily say no but sometimes say yes. It might still be a while before ADB comes to the States. And even when it does, it’ll only be allowed, not required, which is a shame—it’ll probably be available only on expensive premium cars, widening the safety gap between the “haves” and “have-nots” that already exists because of the wide performance range even among conventional headlamps.


When should you not use your front fog lamps? Do you know if your car has a rear fog lamp (or even what it is)? How necessary is it to dip your high beams at night on a divided highway? And what about all those “phantom vehicles” traveling at night with only their daytime running lights on?

Answers to these questions coming in Part 2 of my interview of Daniel Stern next week…stay tuned!


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Mi Ae Lipe

Mi Ae Lipe is a citizen advocate living near Seattle, Washington. She blogs on Driving in the Real World, Tweets daily driving news and tips at @DrivingReal, and writes a regular column on street driving for BMW CCA’s Roundel magazine. She frequently collaborates with government organizations, NGOs, and individuals. She and fellow citizen Mark Butcher are recipients of the National Highway Traffic Safety Administration (NHTSA) 2017 Award for Public Service for their work in


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