[the__alchemist]

If this surprises you, consider the alternative: Driving through a yellow being illegal or unexpected doesn't make sense, given the finite stopping distance of cars, and reaction time of humans. This is because the yellow light is the first explicit indicator you must stop.

If this doesn't make sense still, picture this scenario: You are driving at the speed limit. You are 500ms from crossing the stop line threshold. The light turns yellow.

Your interpretation would make sense only if there were a (paler yellow?) light warning of the yellow light!

[Spivak]

Yep, something something Chesterton's fence. If you couldn't drive through a yellow then you effectively have two lights go/stop which makes drivers choose between the safe but illegal thing of running the light or the dangerous but legal thing of slamming on their brakes.

You can't have an instant switch between go/stop which yellow— effectively meaning unsafe stopping distance go, safe stopping distance stop— solves very neatly.

[scotty79]

> effectively meaning unsafe stopping distance go, safe stopping distance stop— solves very neatly.

That's how it works in Poland and it works reasonably well.

On the other hand when light is about to turn green, yellow lights up. So red and yellow at the same time means prepare to go.

[GuB-42]

In France, it is illegal to drive through a yellow light unless it would be dangerous to stop, for example if it required you to break hard. That part is up to the officer judgment.

In practice, I have never seen it applied, and it is only a small fine anyways, much less serious than running a red light. I guess it can be used as an excuse if the police really wants to pull you over.

[chaoskanzlerin]

Austria does that: 4 seconds of the green light flashing in order to announce the yellow light.

[cortesoft]

So a pre-yellow light? This seems like you just changed what we call a yellow light to the 4 flashing greens, and made the yellow the new red. If yellow means “don’t enter the intersection”, how is that different than a red?

[the__alchemist]

With this change to the scenario, being required to stop before yellow makes sense. And blowing through red means you extra screwed up! (?)

On this note: In the UK, there is a yellow light prior to green; love it.

[gowld]

The US sometimes has something similar: visibile countdown timers for the pedestrian crossing turning form stop to go, which coincides with the car light turning from red/stop to green/go.

This encourages people to run the light by trying to turn exactly as the countdown timer hits 0, trying to race against pedestrians trying to cross crossing pedestrians.

[manwe150]

You could always do that before in most instances just by watching for the yellow on the cross street too. Though I think the green is often slightly delayed relative to the pedestrian light, precisely to ensure the car cannot win that race legally

[tbrownaw]

How long until we can get a proper countdown like some pedestrian signals have?

[rlue]

On the contrary, I think it could make perfect sense: What's written in the law is one thing, and how it's enforced is another; I would argue that the former should be done with consideration to the latter.

Based on my own experience, I'd estimate that well over 99% of traffic infractions go entirely ignored by the law: minor speed violations, unsignaled lane changes, rolling stops at stop signs, expired tags, cell phone usage, and yes, running red lights.

When the letter of the law is broader in scope or errs on the side of caution, that enables the police to exercise their judgment in enforcing it (with the obvious caveat that some police will abuse any power you give them). You could imagine a scenario where someone technically runs a red light but it's totally justifiable and safe (heavy load + moderate speed + short yellow + no other traffic) and another where someone technically makes it into the intersection on a yellow light but senselessly severely endangers public safety (busy intersection + rapid acceleration + traffic backed up on the other side of the light).

I would be okay with someone evading a ticket in the first case and getting one in the latter.