4 ms·

There's a bit of a feedback loop in play here too (i.e. Brightness wars). If you have dim headlights and are the only driver on the road, your eyes will adjust

by beloch 9y ago

There's a bit of a feedback loop in play here too (i.e. Brightness wars). If you have dim headlights and are the only driver on the road, your eyes will adjust and you'll see pretty well. If you pass a driver traveling in the opposite direction with dim headlights you'll lose a bit of vision for a little while. Blindingly bright headlights won't necessarily let you see a lot more than dimmer headlights and fully adjusted eyes would. However, if you run into another driver with dim headlights, your eyes won't have to adjust nearly as much and your vision will recover more quickly. The guy with dim lights is going to be blind for a while though. If you want to minimize the time you spend readjusting to your own headlights after passing oncoming traffic, you want brighter lights than anyone else on the road. Not just bright, but brighter. Thus, there's an incentive for headlights to just keep getting brighter and brighter as technology enables this. Solution? Regulate maximum headlight brightness.

thunfischbrot 9y ago
Solution is correct, but you'll never outshine others' headlights shining into your eyes. It's more important that others' bright headlights adjust quickly enough that they do not shine into your eyes. Since the advent on Xenon lights headlights need to automatically adjust so they don't blind drivers. They are just not fast enough or smart enough (shining over a hill crest).
deleted 9y ago
[deleted]
theluketaylor 9y ago
In the US maximum headlight brightness is regulated, but the rules and tests are written extremly poorly. The test is in a specific place at a specific angle, so there are a ton of headlights that can pass the test, but are far brighter everywhere else. Obeying the letter of the law while flaunting the spirit. To make matters worse, due to the way the rules are written advanced systems that dim LED headlights specifically in the path of oncoming cars are not legal in the US. It's becoming common on high end European cars to not just auto dim but isolate oncoming vehicles from illumination while maintaining brightness elsewhere. The key to good regulation here is to write rules about how much light can be experienced by oncoming vehicles of various height and driver positions and let engineers figure out how to meet it.

by beloch 9y ago

thunfischbrot 9y ago

Solution is correct, but you'll never outshine others' headlights shining into your eyes. It's more important that others' bright headlights adjust quickly enough that they do not shine into your eyes. Since the advent on Xenon lights headlights need to automatically adjust so they don't blind drivers. They are just not fast enough or smart enough (shining over a hill crest).

deleted 9y ago

[deleted]

theluketaylor 9y ago

In the US maximum headlight brightness is regulated, but the rules and tests are written extremly poorly. The test is in a specific place at a specific angle, so there are a ton of headlights that can pass the test, but are far brighter everywhere else. Obeying the letter of the law while flaunting the spirit. To make matters worse, due to the way the rules are written advanced systems that dim LED headlights specifically in the path of oncoming cars are not legal in the US. It's becoming common on high end European cars to not just auto dim but isolate oncoming vehicles from illumination while maintaining brightness elsewhere. The key to good regulation here is to write rules about how much light can be experienced by oncoming vehicles of various height and driver positions and let engineers figure out how to meet it.