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Comment by bloak | Hacker News Reader

> Or the speed traps that just trigger a red light.

This sounds interesting. Since when have they been doing this, and do you have a link to photos, video or a more detailed description?

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I don't know when Portugal started this, but in Germany there is at least the concept of a "grüne Well" (literally a green wave). Simply put: if you drive at the speed limit you won't get any red lights. Sadly the german administration barely makes use of this as it doesn't make them any money...

Many cities in the US do this along major roads. They'll time the lights to maximize traffic flow which ussally means if your driving the speed limit you'll at least get through 3-4 lights before you have to stop.

It's a red-light with a speed warning and a detector - if you go over the allowed speed, it turns red, otherwise stays green forever.

But we also have hidden radars which are not announced.

Sounds super dangerous though.

The red light is some distance ahead, not right in front of the speed detector so that you have to immediately hammer down the break pedal and be rear-ended by the vehicle behind.

Of course some will still get as close to the light as they can and hammer the breaks last moment, but they'll do that at other lights too, and other unsafe things, so the danger is not caused by the light in that instance.

Is it a normal light at an intersection, or an extra one somewhere in the middle of a block? It's not hard for me to imagine people scoffing at the mid-block light and deciding to run through it.

Neither I'd say. They're usually on long stretches of old highways with no traffic lights between roundabouts where lots of commercial and residential buildings (and thus people) are right on the curb.

The trick is to drive normal speed and at the very last second speed like a madman, so that it still has to cycle to amber then red just as you leave the intersection!

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