How headlights got brighter, whiter, and more blinding after dark

车灯是如何在夜间变得越来越亮、越来越白、越来越刺眼的

Every so often, I’ll be piloting some sensor-laden, software-defined press car down a dark stretch of highway when an oncoming driver’s high beams arrive like a targeted retinal strike, an involuntary reminder that modern automotive lighting has entered its own lumen arms race. Anyone who has driven at night in the last few years knows what I’m talking about: A modern crossover crests a hill in the opposite lane, and the cabin briefly fills with enough cold-white light to suggest a police helicopter has joined traffic. The obvious assumption is that drivers are simply leaving their high beams on more often, but the reality is more complicated.

每隔一段时间，当我驾驶着一辆装满传感器、由软件定义的媒体试驾车行驶在黑暗的高速公路上时，迎面而来的车辆远光灯总会像精准打击一样直射我的视网膜。这不由得让人想起，现代汽车照明已经进入了一场属于自己的“流明军备竞赛”。过去几年里，任何在夜间开过车的人都明白我在说什么：一辆现代跨界车翻过对向车道的山坡，车厢内瞬间被冷白色的光芒填满，仿佛有一架警用直升机加入了车流。人们很容易认为这是因为司机更频繁地开启了远光灯，但事实远比这复杂。

An old problem

一个古老的问题

Before cars became the modern mode of transportation, horse-drawn carriages used oil lanterns to light the way, as roads were largely unlit outside of towns and cities. These lanterns weren’t particularly bright, though, meaning that after-dark collisions and near-misses were common. The late 1880s brought the motorcar, which used railway-style oil lamps. These emitted light like a candle and were prone to spilling, which could cause the vehicle to ignite. Acetylene lamps arrived in the early 1900s. Like oil lanterns, they were dangerous, primarily because they relied on an open flame and produced highly flammable acetylene gas. If the gas nozzle became clogged or leaked, pockets of concentrated acetylene could build up and ignite, causing localized explosions.

在汽车成为现代交通工具之前，马车使用油灯来照明，因为城镇之外的道路大多没有路灯。然而，这些油灯并不怎么亮，这意味着夜间碰撞和险情频发。19世纪80年代末，汽车问世，最初使用的是铁路风格的油灯。这些灯发出的光像蜡烛一样微弱，而且容易溢出，可能导致车辆起火。20世纪初，乙炔灯出现了。和油灯一样，它们也很危险，主要是因为它们依赖明火，并产生高度易燃的乙炔气体。如果喷嘴堵塞或泄漏，积聚的乙炔气体可能会被点燃，引发局部爆炸。

Setting aside the occasional inferno, early motorcars did at least one thing well: They were faster than the horse-drawn traffic they were busy displacing. The problem, of course, is that this newfound speed arrived in a world whose lighting technology had not quite caught up with the idea of vehicles moving at more than a brisk trot. Early automotive lamps were less like searchlights and more like dim lanterns politely suggesting that there may or may not be a vehicle present.

撇开偶尔发生的火灾不谈，早期的汽车至少有一点做得很好：它们比正在被其取代的马车交通工具更快。当然，问题在于，这种新获得的速度出现在一个照明技术尚未跟上车辆行驶速度的世界里。早期的汽车车灯与其说是探照灯，不如说是昏暗的灯笼，礼貌地暗示着前方可能有一辆车，也可能没有。

From the driver’s perspective, these early headlights did little more than marginally improve visibility. They struggled to illuminate meaningful distance ahead, leaving hazards—including ruts, livestock, and pedestrians—well outside detection range until the last possible moment. Pedestrians had it worse. You might have been walking along a road at night when a faint glow appeared in the distance, followed by the realization that the glow was attached to a rapidly accelerating machine that was not good at noticing you. The entire system effectively relied on mutual improvisation: Drivers guessed where the road went, and pedestrians guessed whether they were about to become part of automotive history.

从驾驶员的角度来看，这些早期的车灯除了略微改善视野外，几乎没有其他作用。它们难以照亮前方有效的距离，导致包括车辙、牲畜和行人在内的危险因素在最后一刻之前都处于探测范围之外。行人的处境更糟。你可能在夜间沿着道路行走，远处出现了一丝微光，随后你意识到那光芒来自一台正在加速行驶、且并不擅长发现你的机器。整个系统实际上依赖于双方的“即兴发挥”：司机猜测道路的走向，而行人则猜测自己是否即将成为汽车历史的一部分。

Getting brighter

变得更亮

Headlight regulation didn’t emerge from a single incident so much as from a steady mismatch between early motor vehicles and roads still designed for horses and pedestrians. Late-19th- and early-20th-century laws in the UK, US cities, and parts of Europe initially treated cars as “locomotives on highways,” requiring only that they carry lamps at night so they could be seen, an intentionally vague standard rooted in carriage-era lighting rules. There was no notion of beam pattern or glare control at first, just basic visibility in otherwise unlit environments.

车灯法规的出现并非源于单一事件，而是源于早期机动车与仍为马匹和行人设计的道路之间持续的不匹配。19世纪末和20世纪初，英国、美国城市和欧洲部分地区的法律最初将汽车视为“公路上的火车”，仅要求它们在夜间携带车灯以便被看见。这是一个植根于马车时代照明规则、故意模糊的标准。起初，并没有光束模式或眩光控制的概念，只是在原本黑暗的环境中提供基本的可见性。

As speeds increased and night driving became routine, these simple visibility requirements gradually hardened into the more technical headlight regulations that shaped modern automotive lighting design. By the early 1900s, complaints from horse riders, pedestrians, and other drivers were already shaping US and European regulations that didn’t just require lamps but also implicitly pushed toward controlled illumination: shielding, positioning, and later beam shaping to reduce dazzle. The tension was visible even then—drivers wanted more forward light as speeds rose, while everyone else wanted fewer blinding lights from oncoming traffic. That trade-off never went away; it just became formalized over time into beam cutoffs, alignment standards, and eventually modern photometric rules that try (with mixed success) to balance visibility for the driver against glare for everyone else.

随着车速提高和夜间驾驶成为常态，这些简单的可见性要求逐渐演变为更具技术性的车灯法规，塑造了现代汽车照明设计。到20世纪初，来自骑马者、行人和司机的投诉已经开始影响美欧法规，这些法规不仅要求安装车灯，还隐含地推动了受控照明：通过遮蔽、定位以及后来的光束整形来减少眩光。即使在当时，这种矛盾也显而易见——司机随着车速提高想要更多的前方照明，而其他人则希望减少迎面而来的刺眼灯光。这种权衡从未消失；它只是随着时间的推移被正式化为光束截止线、对准标准，并最终演变为现代光度规则，试图（尽管效果参差不齐）在驾驶员的视野和对他人的眩光之间取得平衡。

Headlights have become brighter over the past two decades, largely since the automotive industry abandoned the old halogen paradigm in favor of LEDs, HID projectors, and increasingly sophisticated adaptive lighting systems. Older halogen setups, particularly the reflector housings common through the 1980s, 1990s, and early 2000s, produced a comparatively soft, warm beam with limited reach. They were inefficient, generated excessive heat, and scattered light somewhat indiscriminately. But they tended to fail gracefully. Visibility wasn’t exceptional, but neither was the likelihood of accidentally assaulting an oncoming driver’s eyes.

在过去的二十年里，车灯变得越来越亮，这在很大程度上是因为汽车工业放弃了旧的卤素灯模式，转而采用LED、HID投影灯以及日益复杂的自适应照明系统。较旧的卤素灯设置，特别是20世纪80年代、90年代和21世纪初常见的反射式灯罩，产生的光束相对柔和、温暖，照射距离有限。它们效率低下，产生过多的热量，并且光线散射较为随意。但它们的失效方式比较温和。可见性虽然不算出色，但意外刺伤迎面而来司机眼睛的可能性也不高。

Modern systems have an entirely different engineering goal. LEDs consume less power, last far longer, and can emit vastly more light from a much smaller package. Their compactness allows designers to create thinner headlights and more aggressive front-end styling, but it also means the light source itself becomes intensely concentrated. Automakers have additionally shifted toward cooler color temperatures—closer to daylight white than the yellowish glow of old halogens—because we perceive these wavelengths as sharper and more detailed at night. The downside is that blue-white light also produces more glare and discomfort, especially in rain.

现代系统的工程目标则完全不同。LED功耗更低，寿命更长，并且能在更小的体积下发出更多的光。它们的紧凑性使设计师能够创造出更薄的车灯和更具侵略性的前脸造型，但也意味着光源本身变得高度集中。此外，汽车制造商已转向更冷的色温——比旧卤素灯的黄色光更接近日光白——因为我们感知到这些波长在夜间更清晰、细节更丰富。缺点是蓝白光也会产生更多的眩光和不适感，尤其是在雨天。