WEBVTT 00:00:00.000 --> 00:00:03.960 OK, so let's unpack this. We all do it. You get 00:00:03.960 --> 00:00:06.580 in the car. The sun goes down. You twist a knob. 00:00:06.940 --> 00:00:09.119 Or if you're in a newer car, you just let the 00:00:09.119 --> 00:00:11.679 sensors do their thing, and boom, light. Right. 00:00:11.759 --> 00:00:14.080 It feels completely automatic. Yeah. It just 00:00:14.080 --> 00:00:16.359 feels like a basic, boring part of the car. It 00:00:16.359 --> 00:00:20.140 does feel basic, yes. But it is arguably the 00:00:20.140 --> 00:00:22.839 single most critical safety device on the vehicle, 00:00:23.559 --> 00:00:26.800 mostly because of how incredibly dangerous the 00:00:26.800 --> 00:00:29.629 alternative is. And that is exactly where I want 00:00:29.629 --> 00:00:32.130 to start our deep dive today because I was reading 00:00:32.130 --> 00:00:34.570 through the research for this and I found a statistic 00:00:34.570 --> 00:00:37.270 from the National Highway Traffic Safety Administration 00:00:37.270 --> 00:00:40.149 that honestly floored me. I had to read it twice. 00:00:40.289 --> 00:00:42.030 Oh, I think I know the one you mean. Yeah. The 00:00:42.030 --> 00:00:44.850 fatality split. Exactly. So nearly half of all 00:00:44.850 --> 00:00:46.969 traffic related fatalities happen in the dark. 00:00:47.049 --> 00:00:49.929 But here is the kicker context for you. Only 00:00:49.929 --> 00:00:52.890 about 25 percent of all travel actually happens 00:00:52.890 --> 00:00:55.070 during those hours. Right. So you're driving 00:00:55.070 --> 00:00:57.750 way less. There are way fewer cars. on the road, 00:00:58.090 --> 00:01:00.829 but the risk of dying is exponentially higher. 00:01:01.210 --> 00:01:04.090 The risk density is just off the charts. And 00:01:04.090 --> 00:01:07.469 standing between you and that statistic is the 00:01:07.469 --> 00:01:10.129 entire subject of our deep dive today. We're 00:01:10.129 --> 00:01:13.129 looking at the history, the physics, and the 00:01:13.129 --> 00:01:15.510 really surprisingly dramatic politics of the 00:01:15.510 --> 00:01:17.510 automotive headline. Actually, before we go any 00:01:17.510 --> 00:01:19.890 further, I should probably correct myself right 00:01:19.890 --> 00:01:22.079 now, shouldn't I? Because I keep wanting to say 00:01:22.079 --> 00:01:23.959 headlight. Oh, it's the most common mix up in 00:01:23.959 --> 00:01:26.120 the industry. Yeah. But if we want to be precise, 00:01:26.319 --> 00:01:28.420 and for this deep dive we definitely do, the 00:01:28.420 --> 00:01:30.859 headlamp is the actual physical device, the hardware 00:01:30.859 --> 00:01:32.840 installed in the front of the car. Right. The 00:01:32.840 --> 00:01:34.400 headlight is the beam of light that actually 00:01:34.400 --> 00:01:36.599 comes out of it. OK. So headlamp is the hardware. 00:01:36.840 --> 00:01:38.680 Headlight is the beam. I will try to keep that 00:01:38.680 --> 00:01:40.239 straight. See, it takes practice. So today we're 00:01:40.239 --> 00:01:42.060 going on a pretty wild journey. We're going to 00:01:42.060 --> 00:01:45.859 go from literally carrying fire in a box on the 00:01:45.859 --> 00:01:48.760 front of a carriage. Which was. Exactly as dangerous 00:01:48.760 --> 00:01:51.480 and ineffective as it sounds. To the frozen era 00:01:51.480 --> 00:01:53.939 where American law basically banned innovation 00:01:53.939 --> 00:01:57.239 for decades, to the nostalgia of pop -up lights, 00:01:57.239 --> 00:02:00.900 and finally to lasers and matrixes that can essentially 00:02:00.900 --> 00:02:03.620 see around corners. It's a massive trajectory. 00:02:03.700 --> 00:02:06.480 We've gone from burning gas to digitally controlled 00:02:06.480 --> 00:02:09.560 pixels in just over a century. So let's rewind 00:02:09.560 --> 00:02:13.000 way back, before the Model T even, if you were 00:02:13.000 --> 00:02:16.099 driving a horseless carriage in, say, the 1890s 00:02:16.099 --> 00:02:18.930 at night. What were you actually using? Well, 00:02:19.009 --> 00:02:21.349 you're using legacy technology. You're using 00:02:21.349 --> 00:02:24.650 carriage lamps, which were designed for, well, 00:02:24.810 --> 00:02:27.150 carriages pulled by horses. Makes sense. And 00:02:27.150 --> 00:02:29.229 horses, generally speaking, don't move very fast. 00:02:29.370 --> 00:02:31.430 And they have their own eyes. So these lamps 00:02:31.430 --> 00:02:33.849 usually just burn candles. Candles, like literal 00:02:33.849 --> 00:02:36.650 wax candles. Literal wax candles inside a little 00:02:36.650 --> 00:02:39.469 glass box, which, as you can imagine, are terrible 00:02:39.469 --> 00:02:41.750 for speed. If you're doing 20 miles an hour in 00:02:41.750 --> 00:02:44.599 a vibrating metal contraption, A candle is not 00:02:44.599 --> 00:02:46.520 going to show you a pothole until you are already 00:02:46.520 --> 00:02:49.180 in it. And I imagine the wind is an issue. Constantly 00:02:49.180 --> 00:02:51.919 blowing them out. So you obviously needed something 00:02:51.919 --> 00:02:54.280 brighter and tougher. Enter the acetylene era. 00:02:54.879 --> 00:02:57.159 This runs from the late 1880s into the early 00:02:57.159 --> 00:03:00.699 1900s. Acetylene is a combustible gas. It burns 00:03:00.699 --> 00:03:03.780 with an incredibly bright white flame. And crucially, 00:03:03.819 --> 00:03:06.319 the flame is highly resistant to wind and rain. 00:03:06.500 --> 00:03:08.639 So how did you get the gas into the lamp? Did 00:03:08.639 --> 00:03:11.479 you have a tank in the car? Sometimes, yeah. 00:03:11.759 --> 00:03:13.479 There was a system called Presto -O -Lite, which 00:03:13.479 --> 00:03:18.000 was very popular. You'd have this calcium carbide 00:03:18.000 --> 00:03:20.379 gas generator strapped to the running board of 00:03:20.379 --> 00:03:23.479 the car. It would feed gas through these little 00:03:23.479 --> 00:03:26.219 copper pipes up to the lamps. But here is the 00:03:26.219 --> 00:03:28.159 sensory detail that we totally forget today, 00:03:28.240 --> 00:03:30.060 the ritual of it. Right, because you couldn't 00:03:30.060 --> 00:03:33.400 just flip a switch inside the cabin. No way. 00:03:33.620 --> 00:03:36.060 You had to physically stop the car, get out, 00:03:36.120 --> 00:03:38.560 walk to the front, open the glass lens, turn 00:03:38.560 --> 00:03:41.560 on the gas valve, strike a match, and hope the 00:03:41.560 --> 00:03:43.180 wind didn't blow it out or that you didn't put 00:03:43.180 --> 00:03:44.960 it on your fingers. Wow. Then you had to walk 00:03:44.960 --> 00:03:47.479 around and do the other side. It was a very physical 00:03:47.479 --> 00:03:49.560 interaction with the machine. I can definitely 00:03:49.560 --> 00:03:51.639 see why people wanted electricity pretty badly 00:03:51.639 --> 00:03:53.680 at that point. But electric lights existed in 00:03:53.680 --> 00:03:55.860 homes by then, so why not cars? Oh, they tried. 00:03:56.460 --> 00:03:58.680 The clubby electric car had optional electric 00:03:58.680 --> 00:04:02.280 headlamps in 1898. Oh, wow. Early. But there 00:04:02.280 --> 00:04:05.259 were two massive engineering hurdles. First, 00:04:05.400 --> 00:04:07.659 the dynamos the generators needed to power them 00:04:07.659 --> 00:04:10.219 were massive and heavy. But the bigger problem 00:04:10.219 --> 00:04:12.599 was the filament itself. They were too fragile. 00:04:12.860 --> 00:04:15.810 Yeah. Carbon filaments in 1898 were delicate 00:04:15.810 --> 00:04:18.769 things, and the roads back then were incredibly 00:04:18.769 --> 00:04:22.389 rough. Cobblestones, dirt ruts. Right, no smooth 00:04:22.389 --> 00:04:24.930 asphalt. Exactly. The vibration would just shake 00:04:24.930 --> 00:04:26.709 those delicate filaments until they snapped. 00:04:27.050 --> 00:04:28.949 You'd hit one bad bump, and suddenly you were 00:04:28.949 --> 00:04:31.029 in total darkness. So it just wasn't practical 00:04:31.029 --> 00:04:34.449 at all. Not until 1912. That is the real pivot 00:04:34.449 --> 00:04:37.720 point. Yeah. Cadillac integrated the Delco electrical 00:04:37.720 --> 00:04:39.819 ignition and lighting system. It was the first 00:04:39.819 --> 00:04:42.300 modern electrical system. Suddenly, you didn't 00:04:42.300 --> 00:04:44.720 need a match. You just needed a switch. And that 00:04:44.720 --> 00:04:46.959 leads to the next big leap in the 20s, right? 00:04:47.100 --> 00:04:50.459 The Bilux bulb. Right, in 1924. Before this, 00:04:50.680 --> 00:04:52.579 if you wanted a high beam and a low beam, you 00:04:52.579 --> 00:04:55.420 often had complex mechanical dippers or entirely 00:04:55.420 --> 00:04:57.699 separate lights. Which sounds expensive. Very. 00:04:58.259 --> 00:05:00.699 The Bilux bulb put two filaments in one single 00:05:00.699 --> 00:05:03.300 bulb. One for the main beam, one for the dipped 00:05:03.300 --> 00:05:05.920 beam. It is the grandfather of the standard bulb 00:05:05.920 --> 00:05:08.660 we use for almost a century. OK, so we have electric 00:05:08.660 --> 00:05:10.800 lights. We have high and low beams. We are making 00:05:10.800 --> 00:05:14.180 serious progress. But then we hit what I like 00:05:14.180 --> 00:05:17.300 to call the great stagnation, specifically in 00:05:17.300 --> 00:05:20.439 the US. This is such a fascinating piece of regulatory 00:05:20.439 --> 00:05:23.040 history that really shaped the visual identity 00:05:23.040 --> 00:05:26.480 of American cars for decades. Because in 1940, 00:05:26.620 --> 00:05:29.500 the US government handed down a mandate. Yes. 00:05:29.819 --> 00:05:32.459 Every vehicle no matter the size the shape the 00:05:32.459 --> 00:05:35.500 brand or the price had to use two seven inch 00:05:35.500 --> 00:05:39.180 round Sealed beam headlamps and sealed beam meaning 00:05:39.180 --> 00:05:42.180 the lens the reflector and the filament are all 00:05:42.180 --> 00:05:45.060 one permanently fused unit correct if the bulb 00:05:45.060 --> 00:05:47.300 burned out You didn't just change a little bulb. 00:05:47.500 --> 00:05:49.500 You threw the entire glass unit away and bought 00:05:49.500 --> 00:05:51.860 a new one. What was the logic behind that? It 00:05:51.860 --> 00:05:53.879 seems incredibly wasteful. It was actually sound 00:05:53.879 --> 00:05:56.019 engineering at the time. Headlights back then 00:05:56.019 --> 00:05:58.839 had a major problem where moisture and dust would 00:05:58.839 --> 00:06:01.339 leak in behind the lens. Oh, and ruin the mirror? 00:06:01.620 --> 00:06:03.879 Exactly. The silver reflector would tarnish and 00:06:03.879 --> 00:06:06.019 get dull. So the light got dimmer and dimmer 00:06:06.019 --> 00:06:07.920 over time without the driver really noticing, 00:06:07.980 --> 00:06:10.199 which was super dangerous. Sealing the whole 00:06:10.199 --> 00:06:12.860 thing prevented that entirely. OK, so good for 00:06:12.860 --> 00:06:16.220 durability. but bad for design. Terrible for 00:06:16.220 --> 00:06:19.220 design. Imagine being a car designer in the 50s. 00:06:19.319 --> 00:06:21.879 You want to make a sleek, futuristic car, maybe 00:06:21.879 --> 00:06:24.300 a low shark nose. Right. Too bad. You have to 00:06:24.300 --> 00:06:27.220 slap two giant seven inch glass circles on the 00:06:27.220 --> 00:06:30.019 front, upright and exposed. It completely froze 00:06:30.019 --> 00:06:32.500 lighting technology in the U .S. until the 70s. 00:06:32.600 --> 00:06:35.160 Though they did tweak it a little in 1957, right? 00:06:35.160 --> 00:06:37.779 They did. They allowed four slightly smaller 00:06:37.779 --> 00:06:40.480 round lamps, the classic quad headlights you 00:06:40.480 --> 00:06:43.819 see on late 50s and 60s muscle cars. But still, 00:06:44.060 --> 00:06:46.660 round sealed beams only. And meanwhile, Europe 00:06:46.660 --> 00:06:49.040 is just doing its own thing. Europe never mandated 00:06:49.040 --> 00:06:51.639 sealed beams. They stuck with replaceable bulbs 00:06:51.639 --> 00:06:54.620 behind different shaped lenses. So by 1960, you 00:06:54.620 --> 00:06:56.779 see cars like the Ford Tannis or the Citroen 00:06:56.779 --> 00:06:59.600 Ami 6 with rectangular lamps or oval lamps. Which 00:06:59.600 --> 00:07:02.180 was completely illegal in America. Totally illegal. 00:07:02.360 --> 00:07:04.579 And then comes the halogen breakthrough. Huge 00:07:04.579 --> 00:07:08.879 moment. 1962, Europe introduces the H1 halogen 00:07:08.879 --> 00:07:12.019 lamp. It uses a tungsten filament, but it's encased 00:07:12.019 --> 00:07:15.220 with halogen gas, which creates this clever chemical 00:07:15.220 --> 00:07:17.759 cycle that redeposits tungsten back onto the 00:07:17.759 --> 00:07:20.500 filament. So it heals itself? Essentially, yes. 00:07:21.000 --> 00:07:24.279 Result being it burns brighter, hotter, and lasts 00:07:24.279 --> 00:07:27.000 way longer. And let me guess, the U .S. government 00:07:27.000 --> 00:07:30.819 said no thanks? Essentially, yes. Halogens were 00:07:30.819 --> 00:07:33.360 effectively banned in the U .S. because regulations 00:07:33.360 --> 00:07:35.699 had a strict cap on how bright lights could be. 00:07:36.220 --> 00:07:37.939 They basically looked at it and said, that works 00:07:37.939 --> 00:07:41.500 too well. That is wild. It wasn't until 1979, 00:07:41.660 --> 00:07:44.160 almost 20 years later, that halogens sealed beams 00:07:44.160 --> 00:07:46.379 were finally allowed in the States. Two decades 00:07:46.379 --> 00:07:48.620 of driving with dimmer lights just because of 00:07:48.620 --> 00:07:51.459 a regulation. But speaking of different regulations, 00:07:51.540 --> 00:07:53.500 we have to talk about France. Because if you 00:07:53.500 --> 00:07:55.680 watch old movies or look at vintage photos from 00:07:55.680 --> 00:07:59.160 Europe, French cars always had these bright yellow 00:07:59.160 --> 00:08:01.740 headlights. Ah, the selective yellow. This is 00:08:01.740 --> 00:08:05.360 a great story. From 1936 all the way to 1993, 00:08:05.879 --> 00:08:08.139 France required headlamps to emit yellow light, 00:08:08.199 --> 00:08:11.420 not white. Why? Was it just a style choice? Ostensibly, 00:08:11.420 --> 00:08:13.579 it was safety. The French Academy of Sciences 00:08:13.579 --> 00:08:16.100 claimed that yellow light reduced glare and was 00:08:16.100 --> 00:08:18.699 better in fog because the longer wavelength scattered 00:08:18.699 --> 00:08:21.199 less than blue or white light. They argued it 00:08:21.199 --> 00:08:23.160 reduced driver fatigue. But is that actually 00:08:23.160 --> 00:08:26.470 true? The sciences mixed it best. UK research 00:08:26.470 --> 00:08:29.069 in the 60s showed maybe a 3 % improvement in 00:08:29.069 --> 00:08:32.309 visual acuity. But later, Dutch research said 00:08:32.309 --> 00:08:34.789 there was basically zero difference. So if the 00:08:34.789 --> 00:08:37.149 science was that shaky, why keep it for 60 years? 00:08:37.269 --> 00:08:39.250 Well, there's another theory. Protectionism. 00:08:39.350 --> 00:08:41.690 Ah, keeping the foreign cars out. Look at the 00:08:41.690 --> 00:08:45.149 start date. 1936. Tensions in Europe are very 00:08:45.149 --> 00:08:48.230 high. During World War II, the yellow lights 00:08:48.230 --> 00:08:51.149 distinguished French civilian vehicles from military 00:08:51.149 --> 00:08:53.409 ones. Right. But after the war, it acted as a 00:08:53.409 --> 00:08:56.409 very effective trade barrier. If you were a German 00:08:56.409 --> 00:08:58.269 or American automaker and you wanted to sell 00:08:58.269 --> 00:09:00.769 your cars in France, you had to manufacture a 00:09:00.769 --> 00:09:03.090 special separate set of yellow lamps just for 00:09:03.090 --> 00:09:05.909 that one market. Which is a massive hassle. Exactly. 00:09:05.990 --> 00:09:09.009 It gave a slight but real edge to domestic French 00:09:09.009 --> 00:09:11.889 manufacturers. It's amazing how much geopolitics 00:09:11.889 --> 00:09:14.830 is involved in a light bulb. Always. Technology 00:09:14.830 --> 00:09:16.990 never exists in a vacuum. Okay, let's move to 00:09:16.990 --> 00:09:19.580 something a bit more fun. Design. Because even 00:09:19.580 --> 00:09:22.080 though the U .S. had these strict shape laws, 00:09:22.679 --> 00:09:24.539 designers were actively trying to fight back. 00:09:24.820 --> 00:09:26.960 And that battle gave us one of the coolest features 00:09:26.960 --> 00:09:29.500 in automotive history. The pop -up headlight. 00:09:29.799 --> 00:09:33.120 The hidden headlamp. This is a classic case of 00:09:33.120 --> 00:09:36.000 engineers solving a regulatory problem with mechanical 00:09:36.000 --> 00:09:39.320 complexity. How so? Well, designers wanted low, 00:09:39.539 --> 00:09:42.610 sleek aerodynamic hoods. But the US law said 00:09:42.610 --> 00:09:44.850 the headlamps had to be at a certain specific 00:09:44.850 --> 00:09:47.309 height, usually about two feet off the ground, 00:09:47.690 --> 00:09:49.610 and they had to be uncovered circles. So if you 00:09:49.610 --> 00:09:52.750 can't change the light, you just hide it. Exactly. 00:09:53.210 --> 00:09:55.850 You make the hood sleek during the day, and then 00:09:55.850 --> 00:09:58.129 mechanically raise the lights to the legal height 00:09:58.129 --> 00:10:00.559 at night. The first one was actually way back 00:10:00.559 --> 00:10:03.860 on the CORD 810 in 1936. And those were completely 00:10:03.860 --> 00:10:05.840 manual too, right? They were. You had a little 00:10:05.840 --> 00:10:07.679 hand crank on the dashboard. You literally had 00:10:07.679 --> 00:10:09.919 to wind them up like a window. That is true dedication 00:10:09.919 --> 00:10:11.879 to style. Just hold on a second. Let me crank 00:10:11.879 --> 00:10:14.220 up my headlights. But the true golden era was 00:10:14.220 --> 00:10:17.779 the 60s and 70s. The Corvette, the Ferrari Daytona, 00:10:17.919 --> 00:10:20.360 the Lamborghini Countach. It allowed the car 00:10:20.360 --> 00:10:22.279 to look like a wedge cutting through the air. 00:10:22.659 --> 00:10:25.240 So cool. And at night, vacuum -operated servos 00:10:25.240 --> 00:10:27.340 or electric motors would kick in and pop. Up 00:10:27.340 --> 00:10:29.480 come the lights. But there is a real victim of 00:10:29.480 --> 00:10:32.620 the US regulations in this era too, the Jaguar 00:10:32.620 --> 00:10:35.620 E -Type. Oh, an absolute tragedy for car lovers. 00:10:36.200 --> 00:10:38.340 The original E -Type is widely considered one 00:10:38.340 --> 00:10:40.320 of the most beautiful cars ever made. Right up 00:10:40.320 --> 00:10:42.639 there. It had these lovely sculpted glass covers 00:10:42.639 --> 00:10:44.899 over the headlights to make them perfectly aerodynamic, 00:10:45.500 --> 00:10:48.100 following the exact curve of the fender. Then 00:10:48.100 --> 00:10:53.580 in 1968, the US passed FMVSS 108, which explicitly 00:10:53.580 --> 00:10:56.200 banned covered lights. Why ban the glass cover? 00:10:56.399 --> 00:10:58.279 They were worried about the glass reducing the 00:10:58.279 --> 00:11:00.179 light output or getting dirty and reflecting 00:11:00.179 --> 00:11:03.360 glare. So Jaguar had to remove the glass and 00:11:03.360 --> 00:11:05.860 just leave these naked scoops in the hood. Which 00:11:05.860 --> 00:11:08.340 ruined the lines. Completely wrecked the drag 00:11:08.340 --> 00:11:10.259 coefficient and the whole look of the front end. 00:11:10.500 --> 00:11:13.879 So what finally killed the pop -up? Because you 00:11:13.879 --> 00:11:16.000 just do not see them anymore. Was it aerodynamics? 00:11:16.279 --> 00:11:19.519 No, it was safety again. But this time, pedestrian 00:11:19.519 --> 00:11:22.840 safety? Pedestrians? How do headlights hurt pedestrians? 00:11:23.100 --> 00:11:25.539 Think about the physics of an impact. You have 00:11:25.539 --> 00:11:28.460 a sleek car, but then you have these two rigid, 00:11:28.759 --> 00:11:31.159 sharp metal boxes sticking up straight from the 00:11:31.159 --> 00:11:34.120 hood. Oh, I see. If you hit a pedestrian, those 00:11:34.120 --> 00:11:37.519 pop -ups act like rigid protuberances. They cause 00:11:37.519 --> 00:11:40.360 severe injuries. So global regulations changed 00:11:40.360 --> 00:11:43.480 to limit sharp angles on hoods. And by 2004, 00:11:43.659 --> 00:11:46.690 the pop -up was effectively dead. RIP to the 00:11:46.690 --> 00:11:48.610 pop -up. Now I want to get into the physics of 00:11:48.610 --> 00:11:51.169 this a little bit, because we talk casually about 00:11:51.169 --> 00:11:53.870 high beams and low beams, but there is actually 00:11:53.870 --> 00:11:56.529 a really complex geometry happening in that beam 00:11:56.529 --> 00:11:58.850 pattern. There really is. It is not just dim 00:11:58.850 --> 00:12:02.769 and bright. It is entirely about aim. A high 00:12:02.769 --> 00:12:05.350 beam is center -weighted. It throws light as 00:12:05.350 --> 00:12:06.990 straight and as far down the road as physically 00:12:06.990 --> 00:12:09.250 possible. Because it doesn't care about blinding 00:12:09.250 --> 00:12:11.210 anyone, since you only use it when you're alone. 00:12:11.710 --> 00:12:14.429 Precisely. But low beams have to play nice with 00:12:14.429 --> 00:12:16.909 others. Low beams have what we call a cutoff. 00:12:17.370 --> 00:12:19.169 If you shine your car lights against a brick 00:12:19.169 --> 00:12:21.610 wall, you will see a sharp horizontal line where 00:12:21.610 --> 00:12:24.129 the light just stops. Right. But it's not a perfectly 00:12:24.129 --> 00:12:26.990 straight horizontal line across. No, it is asymmetrical. 00:12:27.070 --> 00:12:29.169 In the US and Europe, where we drive on the right 00:12:29.169 --> 00:12:31.610 side of the road, the beam dips low on the left 00:12:31.610 --> 00:12:33.950 to avoid blinding oncoming drivers. But then 00:12:33.950 --> 00:12:36.429 it steps up on the right. Exactly. It kicks up 00:12:36.429 --> 00:12:38.690 on the right side to illuminate road signs and 00:12:38.690 --> 00:12:41.299 pedestrians walking on the shoulder. And this 00:12:41.299 --> 00:12:44.279 creates a very specific issue for travelers. 00:12:44.559 --> 00:12:46.919 I saw a term in the sources called the travelers 00:12:46.919 --> 00:12:50.399 problem. Oh yes. This is a classic headache for 00:12:50.399 --> 00:12:52.340 anyone driving across borders with different 00:12:52.340 --> 00:12:55.799 traffic signs. Say you take a British car, which 00:12:55.799 --> 00:12:58.220 is obviously designed for driving on the left. 00:12:58.559 --> 00:13:00.919 And you take it on a ferry into France. Right. 00:13:01.049 --> 00:13:03.149 where they drive on the right. Yeah. Your kick 00:13:03.149 --> 00:13:06.490 up is now on the wrong side. Oh no. Your lights 00:13:06.490 --> 00:13:08.830 are dipping to the left, which is now the shoulder, 00:13:09.190 --> 00:13:11.330 and they are kicking up to the right directly 00:13:11.330 --> 00:13:14.129 into the eyes of every oncoming French driver. 00:13:14.370 --> 00:13:17.330 You're blinding everyone. So how do you fix that 00:13:17.330 --> 00:13:19.750 if you're just on vacation? Historically, you 00:13:19.750 --> 00:13:22.210 had to buy these little opaque decals or stickers 00:13:22.210 --> 00:13:24.929 at the ferry terminal and physically stick them 00:13:24.929 --> 00:13:28.029 onto your headlamp lens to block that specific 00:13:28.029 --> 00:13:30.490 part of the beam. It's a legal requirement. That 00:13:30.490 --> 00:13:32.789 seems incredibly low tech for driving a modern 00:13:32.789 --> 00:13:35.169 machine. It is, though. A lot of modern cars 00:13:35.169 --> 00:13:37.309 have a software setting in the dashboard now 00:13:37.309 --> 00:13:40.330 that adjusts the matrix. But speaking of beam 00:13:40.330 --> 00:13:43.049 patterns, there is a massive philosophical debate 00:13:43.049 --> 00:13:45.070 in the lighting world between the US system, 00:13:45.289 --> 00:13:47.970 which is SAE, and the rest of the world, which 00:13:47.970 --> 00:13:51.190 uses ECE. What's the core difference? Isn't light 00:13:51.190 --> 00:13:55.029 just light? You would think. But the safety philosophy 00:13:55.029 --> 00:13:57.669 is fundamentally different. The ECE, the European 00:13:57.669 --> 00:14:00.529 standard, prioritizes preventing glare at all 00:14:00.529 --> 00:14:03.529 costs. They require a remarkably sharp cutoff. 00:14:03.809 --> 00:14:05.929 So below the line is bright, above the line is 00:14:05.929 --> 00:14:08.190 dark. Almost total darkness above the line, yes. 00:14:08.309 --> 00:14:11.090 And the U .S. The SAE standard actively allows 00:14:11.090 --> 00:14:13.210 for more scatter light above that horizontal 00:14:13.210 --> 00:14:15.720 line. Why would they want scatter? The argument 00:14:15.720 --> 00:14:18.960 is that America has vast, dark highways, and 00:14:18.960 --> 00:14:21.539 you need some ambient light thrown upwards to 00:14:21.539 --> 00:14:24.100 read large overhead highway signs that aren't 00:14:24.100 --> 00:14:26.299 internally illuminated. But that upward scatter 00:14:26.299 --> 00:14:29.220 directly equals glare for the oncoming driver. 00:14:29.440 --> 00:14:31.840 Exactly. It is deliberate tradeoff. The U .S. 00:14:32.000 --> 00:14:33.980 accepts a bit more glare to ensure you can read 00:14:33.980 --> 00:14:36.720 the exit sign from further away. Europe says 00:14:36.720 --> 00:14:38.860 no, keep the light rigidly on the road. Is one 00:14:38.860 --> 00:14:41.200 actually better? Studies show neither system 00:14:41.200 --> 00:14:44.429 is definitively safer. It mostly comes down to 00:14:44.429 --> 00:14:46.669 what drivers in that region are culturally used 00:14:46.669 --> 00:14:49.450 to. Well, speaking of glare, let's talk about 00:14:49.450 --> 00:14:51.830 the blue lights. The ones that absolutely everyone 00:14:51.830 --> 00:14:54.490 complains about on the highway. Ah, the HID wars. 00:14:54.909 --> 00:14:57.950 High -intensity discharge. Also commonly known 00:14:57.950 --> 00:15:00.429 as xenon. Who's first shit up in the 90s? Yes, 00:15:00.690 --> 00:15:04.789 first on the BMW 7 Series. Technically, they 00:15:04.789 --> 00:15:07.610 are arc lamps. There is no traditional filament 00:15:07.610 --> 00:15:10.259 at all. So how does it glow? It's a spark of 00:15:10.259 --> 00:15:12.639 electricity jumping between two tungsten electrodes 00:15:12.639 --> 00:15:15.539 inside a tiny quartz capsule filled with xenon 00:15:15.539 --> 00:15:18.840 gas and metal salts. It is quite literally a 00:15:18.840 --> 00:15:20.720 controlled lightning bolt in a bottle. And they 00:15:20.720 --> 00:15:24.000 are incredibly bright. Very. To put it in perspective, 00:15:24.179 --> 00:15:27.620 a standard halogen puts out maybe 1 ,400 lumens. 00:15:28.139 --> 00:15:31.000 An early HID puts out 3 ,000. More than double. 00:15:31.179 --> 00:15:32.799 But the real issue is the color temperature. 00:15:33.080 --> 00:15:35.259 They produce a very crisp white -blue light. 00:15:35.360 --> 00:15:37.139 And that's what makes people so angry when they 00:15:37.139 --> 00:15:40.350 drive past them. Yes. Because human eyes react 00:15:40.350 --> 00:15:42.950 differently to blue light, it appears far more 00:15:42.950 --> 00:15:45.970 piercing to us. Studies have shown that even 00:15:45.970 --> 00:15:49.110 at the exact same measured intensity, an HID 00:15:49.110 --> 00:15:52.529 light is perceived as 40 % more glaring to other 00:15:52.529 --> 00:15:55.009 drivers than the warm yellowish halogen light. 00:15:55.409 --> 00:15:57.169 But the driver sitting behind the wheel loves 00:15:57.169 --> 00:15:59.389 it. Oh, the driver feels invincible. You feel 00:15:59.389 --> 00:16:01.129 like you have high -definition night vision. 00:16:01.490 --> 00:16:03.870 It's a classic conflict of the driver's experience 00:16:03.870 --> 00:16:06.500 versus the oncoming traffic's experience. And 00:16:06.500 --> 00:16:09.279 then came LEDs. The Audi R8 brought those to 00:16:09.279 --> 00:16:12.379 the mass market around 2007. Light emitting diodes, 00:16:12.539 --> 00:16:14.940 yes. They are hyper efficient, they're physically 00:16:14.940 --> 00:16:17.840 tiny, and they allow for crazy design signatures 00:16:17.840 --> 00:16:19.600 because you don't need a massive round reflector. 00:16:19.720 --> 00:16:22.799 But they introduced a really funny new engineering 00:16:22.799 --> 00:16:25.639 problem, the cold lens. The cold lens. What does 00:16:25.639 --> 00:16:28.320 that mean? Think about the older lights. Halogens 00:16:28.320 --> 00:16:31.059 and HIDs generate a massive amount of waste heat. 00:16:31.600 --> 00:16:34.080 So if you were driving in a snowstorm, the heat 00:16:34.080 --> 00:16:36.139 from the bulb naturally melts the snow right 00:16:36.139 --> 00:16:38.379 off the front lens. Oh, they self -clean. I never 00:16:38.379 --> 00:16:41.639 even thought about that. Exactly. But LEDs are 00:16:41.639 --> 00:16:44.600 so efficient they don't emit infrared heat forward. 00:16:45.039 --> 00:16:47.220 So you could be driving an ultra modern car in 00:16:47.220 --> 00:16:50.240 a blizzard and your headlights just get completely 00:16:50.240 --> 00:16:51.899 caked in snow and ice because they aren't hot 00:16:51.899 --> 00:16:53.799 enough to melt it off. So you're just driving 00:16:53.799 --> 00:16:56.679 blind. What was the fix? They literally had to 00:16:56.679 --> 00:17:00.240 engineer tiny internal fans or specialized heating 00:17:00.240 --> 00:17:02.860 elements into the housing just to blow warm air 00:17:02.860 --> 00:17:05.559 onto the plastic to thaw it. It's a perfect case 00:17:05.559 --> 00:17:08.779 of new tech solving one problem energy use but 00:17:08.779 --> 00:17:11.039 instantly creating a completely new one. Welcome 00:17:11.039 --> 00:17:13.099 to automotive engineering. We've also got lasers 00:17:13.099 --> 00:17:15.619 now, which honestly just sounds like science 00:17:15.619 --> 00:17:18.759 fiction. It does. Cars like the BMW i8 and the 00:17:18.759 --> 00:17:22.440 Audi R8 LMX use them. But don't worry, they aren't 00:17:22.440 --> 00:17:24.640 shooting a raw laser beam into your retina. Good 00:17:24.640 --> 00:17:26.839 to know. How does it actually work, then? Tiny 00:17:26.839 --> 00:17:29.559 mirrors direct a blue laser onto a special yellow 00:17:29.559 --> 00:17:32.680 phosphorus lens. When the laser hits the phosphorus, 00:17:32.920 --> 00:17:35.839 it gets excited and emits a brilliant, pure white 00:17:35.839 --> 00:17:38.160 light. So the laser is just the power source 00:17:38.160 --> 00:17:42.039 for the glowing phosphorus. Exactly. And it is 00:17:42.039 --> 00:17:45.380 incredibly energy -dense. Half the power draw 00:17:45.380 --> 00:17:49.000 of LEDs. The Rolls -Royce Phantom 8. uses lasers 00:17:49.000 --> 00:17:51.960 to cast a high beam 600 meters down the road. 00:17:52.460 --> 00:17:54.740 600 meters. That is more than half a kilometer 00:17:54.740 --> 00:17:58.180 of pure visibility. It's staggering range. But 00:17:58.180 --> 00:18:01.039 range isn't everything anymore. We are now firmly 00:18:01.039 --> 00:18:03.880 entering the era of smart lights. Which brings 00:18:03.880 --> 00:18:07.680 us to adaptive front lighting systems, or AFS. 00:18:07.960 --> 00:18:10.420 Now this isn't a brand new idea, is it? You mentioned 00:18:10.420 --> 00:18:14.140 the Tucker 48 earlier. Yes, the 1948 Tucker Torpedo. 00:18:14.349 --> 00:18:16.650 It had a third headlight mounted right in the 00:18:16.650 --> 00:18:18.369 center of the hood that was mechanically connected 00:18:18.369 --> 00:18:20.630 to the steering linkage. So if you turn the wheel 00:18:20.630 --> 00:18:23.029 left, the light physically looked left. Simple, 00:18:23.329 --> 00:18:25.369 mechanical, and brilliant. The Citroen DS did 00:18:25.369 --> 00:18:27.450 it in the late 60s with a really complex system 00:18:27.450 --> 00:18:29.910 of cables and ropes. Piano wire, essentially. 00:18:30.309 --> 00:18:32.609 But modern AFS does the exact same concept using 00:18:32.609 --> 00:18:35.089 GPS and steering angle sensors. It knows a curve 00:18:35.089 --> 00:18:36.890 is coming before you even turn the wheel, and 00:18:36.890 --> 00:18:39.089 it swivels the LED modules to illuminate into 00:18:39.089 --> 00:18:43.240 the bend. That is cool! But the holy grail right 00:18:43.240 --> 00:18:46.299 now has to be the matrix light the glare free 00:18:46.299 --> 00:18:48.839 high beam I have seen videos of this in action 00:18:48.839 --> 00:18:51.099 and it genuinely looks like magic. It is the 00:18:51.099 --> 00:18:54.059 biggest leap forward in decades So imagine driving 00:18:54.059 --> 00:18:56.059 down a pitch -black road with your high beams 00:18:56.059 --> 00:18:59.720 on constantly maximum brightness Never dipping 00:18:59.720 --> 00:19:02.000 them. You would be the most hated person on the 00:19:02.000 --> 00:19:06.539 highway normally. Yes but with matrix LED a forward 00:19:06.539 --> 00:19:10.440 -facing camera scans for other cars when it sees 00:19:10.440 --> 00:19:14.500 one say, an oncoming semi truck, it doesn't dip 00:19:14.500 --> 00:19:16.940 the whole headlight beam. What does it do? It 00:19:16.940 --> 00:19:19.880 selectively turns off individual LED pixels within 00:19:19.880 --> 00:19:21.819 the light cluster. So it basically draws a black 00:19:21.819 --> 00:19:24.000 box around the other car? Exactly. It creates 00:19:24.000 --> 00:19:26.539 a dynamic shadow tunnel. The other driver is 00:19:26.539 --> 00:19:28.160 sitting perfectly in the dark, totally comfortable. 00:19:28.839 --> 00:19:31.039 But everywhere else, the trees, the deer on the 00:19:31.039 --> 00:19:32.839 shoulder, the empty road ahead is still lit up 00:19:32.839 --> 00:19:35.039 with full high beam intensity. And it tracks 00:19:35.039 --> 00:19:36.819 them? It tracks the car as it moves, keeping 00:19:36.819 --> 00:19:38.779 it locked in that shadow block while lighting 00:19:38.779 --> 00:19:41.069 up the rest of the world around it. That sounds 00:19:41.069 --> 00:19:43.650 absolutely incredible for nighttime safety. Why 00:19:43.650 --> 00:19:45.630 don't we see these on every car in the U .S.? 00:19:45.630 --> 00:19:47.549 I feel like I've only seen them on European car 00:19:47.549 --> 00:19:50.009 reviews. We were right back to regulations. The 00:19:50.009 --> 00:19:53.849 U .S. law, FMVSS 108, was written decades ago 00:19:53.849 --> 00:19:56.609 in a way that rigidly defined a quote unquote 00:19:56.609 --> 00:19:59.529 high beam and a low beam. It didn't have any 00:19:59.529 --> 00:20:01.670 legal framework for a high beam with dynamic 00:20:01.670 --> 00:20:04.289 dark holes carved into it. So it was just illegal 00:20:04.289 --> 00:20:08.109 by default? Until 2022. Yes. The Audi Matrix 00:20:08.109 --> 00:20:09.869 system, for example, has been legal in Europe 00:20:09.869 --> 00:20:12.329 for years. But if you bought that same car in 00:20:12.329 --> 00:20:14.750 the U .S., the automakers actually had to use 00:20:14.750 --> 00:20:17.369 software to permanently disable the Matrix feature 00:20:17.369 --> 00:20:19.869 before selling it to you. That is so frustrating. 00:20:20.269 --> 00:20:22.809 The U .S. finally amended the rule in 2022 to 00:20:22.809 --> 00:20:25.190 allow it. But the specific testing requirements 00:20:25.190 --> 00:20:27.109 are still slightly different from the international 00:20:27.109 --> 00:20:29.750 standard. So it is taking time for manufacturers 00:20:29.750 --> 00:20:32.029 to certify and roll them out here. It's always 00:20:32.029 --> 00:20:34.750 the paperwork, isn't it? Always. Innovation moves 00:20:34.750 --> 00:20:37.329 at the speed of light. But regulation moves at 00:20:37.329 --> 00:20:39.890 the speed of a committee. So we have gone from 00:20:39.890 --> 00:20:42.549 literally burning acetylene gas tanks strapped 00:20:42.549 --> 00:20:45.529 to the running board, all the way to digitally 00:20:45.529 --> 00:20:48.230 controlled pixels that can actively dodge oncoming 00:20:48.230 --> 00:20:51.329 cars. It has been a massive evolution. It really 00:20:51.329 --> 00:20:54.269 has. And I think the major takeaway here is that 00:20:54.269 --> 00:20:56.690 lighting isn't just about seeing. What else is 00:20:56.690 --> 00:20:59.759 it about? It is about communication. It is a 00:20:59.759 --> 00:21:02.380 constant act of negotiation between you and the 00:21:02.380 --> 00:21:03.920 other drivers out there. Right. It's a battle 00:21:03.920 --> 00:21:06.380 between physics and physiology. Exactly. You 00:21:06.380 --> 00:21:09.160 need to see the assured clear distance to stop 00:21:09.160 --> 00:21:12.819 in time. But if your super bright laser light 00:21:12.819 --> 00:21:15.000 prevents the other guy from seeing his lane, 00:21:15.380 --> 00:21:17.259 you have just created a totally different hazard. 00:21:17.420 --> 00:21:19.480 So here is my final thought for you to chew on 00:21:19.480 --> 00:21:22.859 as we wrap up. We are rapidly moving toward a 00:21:22.859 --> 00:21:26.170 world of autonomous vehicles. Cars that drive 00:21:26.170 --> 00:21:28.730 themselves. Right. They use LiDAR. They use radar. 00:21:28.890 --> 00:21:31.349 They use cameras that can see perfectly in infrared. 00:21:31.589 --> 00:21:34.150 They don't need visible spectrum light to drive 00:21:34.150 --> 00:21:37.069 safely. Exactly. So in, say, 20 years, if the 00:21:37.069 --> 00:21:39.750 car is doing all the driving, do we even need 00:21:39.750 --> 00:21:42.349 headlights anymore? Or are the lights just going 00:21:42.349 --> 00:21:44.029 to be there for the pedestrians so that we can 00:21:44.029 --> 00:21:47.170 see the car coming? That is a fascinating question. 00:21:48.170 --> 00:21:50.170 The headlamp might transform from a critical 00:21:50.170 --> 00:21:53.450 tool for the driver into a pure warning beacon 00:21:53.450 --> 00:21:56.609 for everyone outside the car. Or maybe they just 00:21:56.609 --> 00:21:59.089 disappear entirely. Something to think about 00:21:59.089 --> 00:22:02.029 the next time you flip that switch. Thanks for 00:22:02.029 --> 00:22:04.309 listening to this deep dive into the world of 00:22:04.309 --> 00:22:06.589 automotive headlamps. Drive safe out there. See 00:22:06.589 --> 00:22:07.089 you next time.