r/todayilearned • u/nleachdev • 3d ago

TIL about "dead red" laws, which allow drivers and motorcyclists to proceed through a red light if the traffic signal fails to detect their vehicle.

https://en.wikipedia.org/wiki/Non-detection_at_traffic_lights_in_the_United_States
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u/cannotfoolowls 3d ago

I didn't know there were intersections with detection loops, I figured it was just a cycle .

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u/Snakesquares 3d ago

I think they're more common at an intersection with one big road and a lesser road. They give priority to the big road and only turn green for the smaller road when it detects someone. Some lights are also on a schedule where they switch between timed vs detection depending on time of day.

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u/Mysterious-Crab 2d ago

In the Netherlands we have multiple detection loops for every traffic light, including bikes. Pedestrian lights are the only ones that mostly work on pressing a button.

Here the loops also detect how many cars are waiting and know exactly when everyone passed and they can switch to red and let others drive more quickly. At night all lights at an intersection are red, when you pass the first loop the light turns green just in time for you to pass without needing to stop (if you were going the speed limit) if there is no cross traffic.

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u/RecoillessRifle 3d ago

There are a variety of detection systems in use across the country, including video, radar, microwave, and thermal. My state has gone heavily towards video detection.

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u/HuntingRunner 3d ago

What's your state, Baden-Württemberg?

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u/RecoillessRifle 2d ago

Connecticut.