Wacky headlight pattern?

[Dave Cundiff]

My understanding is that European standards require the headlight beams to be software-adjusted in real time in order to maximize lighting while not blinding oncoming traffic.

My understanding is that U.S. standards forbid any adjustment other than switching from a predetermined low-beam configuration to a predetermined high-beam configuration and back.

Seems to me that the European standards, as I understand them, would be the safer of the two. Interested in others' perspectives on this....

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[racekarl]

My understanding is that European standards require the headlight beams to be software-adjusted in real time in order to maximize lighting while not blinding oncoming traffic.

My understanding is that U.S. standards forbid any adjustment other than switching from a predetermined low-beam configuration to a predetermined high-beam configuration and back.

Seems to me that the European standards, as I understand them, would be the safer of the two. Interested in others' perspectives on this....

Your understanding is mostly wrong, so there's a perspective for you!

European regulations do not require lights to be real-time adjustable. EU vehicle regulations are of the "type certification" variety, meaning that each new vehicle model must be separately tested for compliance. These tests are sometimes a bit subjective in nature and focus on the outcome rather than the method of accomplishing it. A simplified example would be: tester gets into an "oncoming" car under certain conditions and evaluates how blinded they are by the car under test. If the tester deems the experience acceptable, the new model passes. This allows some leeway in how that is accomplished, so software-controlled lights that "see" oncoming cars and selectively dim the lights shining at them are A-OK as long as they don't blind the tester.

The US by contrast uses a "self-certify against specific standards" approach. US vehicle laws are very prescriptive, and describe in exacting detail how car parts must be tested and produce finely measured results. These tests are designed to be built and run by the manufacturer, with the idea being that a car is OK as long as it can be said to be built to the standard and passed all the tests; a sort of "trust but verify" approach. In this sort of framework, the pace of change can be slower because a new idea like software controlled lights has to have a test framework built for it and specs written so that the government can tell a car manufacturer: "If you do it this way, it will be acceptable." While it took a while, computer-controlled beam-shaping headlights ARE legal in the US.

There isn't really one approach that's inherently better than the other, it's just two different ways to approach the problem, each with advantages and disadvantages.

 

[Dave Cundiff]

Your understanding is mostly wrong, so there's a perspective for you!

European regulations do not require lights to be real-time adjustable. EU vehicle regulations are of the "type certification" variety, meaning that each new vehicle model must be separately tested for compliance. These tests are sometimes a bit subjective in nature and focus on the outcome rather than the method of accomplishing it. A simplified example would be: tester gets into an "oncoming" car under certain conditions and evaluates how blinded they are by the car under test. If the tester deems the experience acceptable, the new model passes. This allows some leeway in how that is accomplished, so software-controlled lights that "see" oncoming cars and selectively dim the lights shining at them are A-OK as long as they don't blind the tester.

The US by contrast uses a "self-certify against specific standards" approach. US vehicle laws are very prescriptive, and describe in exacting detail how car parts must be tested and produce finely measured results. These tests are designed to be built and run by the manufacturer, with the idea being that a car is OK as long as it can be said to be built to the standard and passed all the tests; a sort of "trust but verify" approach. In this sort of framework, the pace of change can be slower because a new idea like software controlled lights has to have a test framework built for it and specs written so that the government can tell a car manufacturer: "If you do it this way, it will be acceptable." While it took a while, computer-controlled beam-shaping headlights ARE legal in the US.

There isn't really one approach that's inherently better than the other, it's just two different ways to approach the problem, each with advantages and disadvantages.

Thanks, @racekarl! I love it when somebody can teach me something!

That happens a lot on this forum.... Much appreciated!

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