[mrandish]

Yes, this intersection has that. The problem is the sensor starts a timer that's set to 2 or 3 minutes for most of the day. This becomes a minimum wait time even when there are no oncoming cars for the entire wait period. At this intersection, the wastefully pointless "idle there for 3 minutes with no other cars anywhere in sight" scenario happens quite often.

There's also an even more perverse failure mode: we often end up waiting for 2.5 minutes with no other cars anywhere in sight, then when a lone car is randomly approaching the light that's been green for no cars (going its way) for 2.5 minutes, that one car gets stopped and waits as we finally get our turn arrow after 3 minutes. If the light was the least bit "smart", it would have changed for us right when we pulled up and no other cars were in sight. The turn arrow is only 10 seconds, so we would have been long gone and the intersection back to green by the time that other car was approaching - no car would have needed to wait and everyone would have been better served.

[xattt]

My local municipality decided that it would be more appropriate for lights to flash yellow and/or red on a couple of low-traffic intersections along major routes between 11 PM and 6 AM.

[ghaff]

I have a few intersections near me that desperately needed to have the lights added but only for busy times of day. At night it can take 5 minutes to get through a battery of lights even with virtually no traffic.

I suspect choosing not to flash them at night is some combination of people not really familiar with that system getting potentially confused and (these are somewhat complex intersections) others just getting careless rather than carefully checking, at night, all the directions that traffic could be coming from.

[prmoustache]

That is the beauty of roundabouts, they work regardless of the time of day, and on some where there is a need for more regulation you can still add lights before the roundabout.

[ghaff]

The lights near me were to tame chaos at an existing intersection.

A big roundabout I use semi-regularly does indeed handle 4 busy roads coming together well at night even if it’s a nightmare at rush hour.

[mrandish]

I've seen that some places as well but I haven't seen it done in the daytime for some reason.

[PaulHoule]

https://usa.streetsblog.org/2018/10/30/for-a-more-walkable-c...

[Filligree]

There's a few intersections like that here in Dublin.

But they aren't marked. So what sometimes happens is I cruise up on a bike, in the middle of the road because none of those have bike lanes.. and the bike, naturally, never triggers the lights. Neither does the car behind me.

[mrandish]

Sorry to hear it's not only a problem here in the U.S. Ideally, our intersection wouldn't have dedicated left turn arrows at all, since it doesn't need them most of the day. The problem arises only about four hours a day. At those times the otherwise empty thoroughfare turns into a wave of cars making it impossible to enter or leave our neighborhood street by turning left because there's rarely a large enough gap in the fast-flowing traffic.

Traffic engineers probably have a term for this kind of bi-polar intersection. A solution would be some kind of "conditional left arrow" but there's no such thing (at least here in the U.S.) If there's a dedicated green arrow for left turn, then there's a modal left-turn red arrow along with it. It should be possible to improve all scenarios by standardizing something like a flashing yellow arrow to mean "okay to cross if no oncoming traffic" since this already works as the default behavior at intersections with no lights or lights with no left turn arrows.

[rootusrootus]

> flashing yellow arrow to mean "okay to cross if no oncoming traffic"

That's already a thing, unless I'm misunderstanding you. We've had flashing yellow left turn arrows for years. I'm in the PNW, but I've seen it in other places in the US, we're definitely not unique.

[Filligree]

There's no left arrow? The sole traffic lights just never turn green.

[doubled112]

I used to make note of these and run up to push the pedestrian crossing button if there was one.

It is the only way the system will realize you are waiting.

[WalterBright]

> the wastefully pointless "idle there for 3 minutes with no other cars anywhere in sight" scenario happens quite often.

The climate activists should be focused on solving that problem.

[mrandish]

While the potential of super-smart AI to improve transport efficiency, costs and environmental impact with self-driving is obvious, it's also expensive and still many years from being ready for broad deployment. It's puzzling that low-hanging fruit like an AI-assisted "Slightly Smarter" traffic light is ignored. It could deliver meaningful improvement today with cheap, easy to retrofit, Raspberry Pi-level tech which already works well enough for a simple, limited use case like reducing unnecessary idling at traffic lights.

[jerezzprime]

For this situation, and similar ones, there are simple solutions. For example, in this situation, the timer should always be running (and resets when the light changes). When a car triggers the sensor, the light should change if the timer is > N. If the timer is not there yet, wait until timer is N.

No AI required, just basic thoughtfulness and requirements gathering.

[WalterBright]

The trouble with the street sensors is that your car has to come to a stop before it is detected. Stopping and starting cars consumes a great deal of gasoline.

Contrast it with the flow achieved when there's a traffic cop managing an intersection. It's an enormous improvement.

[jasonkester]

Don’t American cars have that thing that turns your engine off every time you stop? I can’t remember a car I’ve driven in Europe in the last 15 years that didn’t have that annoying feature.

Annoying because there are hardly any stoplights here. So it works by killing the engine for one second at the first roundabout you roll up to before you remember to hit the button that disables it for the rest of the trip.

I always thought they would work great in the states.

[barbazoo]

Right, let’s make fun of people that actually care about the planet, that’s a really clever thing to do.

[nickpp]

> actually care about the planet

Shouldn't they have been pro-nuclear if they actually cared about the planet? But it seems to me they really care more about pushing their own ideology instead.

[barbazoo]

> Shouldn't they have been pro-nuclear if they actually cared about the planet?

Do you know that "they" aren't? Who is "they" even? None of this makes any sense. This is arguing against a group that is imagined to be homogeneous when that's clearly not the case.

[darby_eight]

? Is this a joke

[hedora]

In the South SF Bay Area, our pickup truck gets 13 mpg mixed freeway/city.

Doing 75-80 on flat land, or 65-70 over the Sierra Nevadas, it gets 24 mpg. With city traffic in other cities it gets 18 mpg.

The reason it is so bad here is that the environmental activists passed traffic quiescence laws that try to discourage people to drive by making the roads worse.

Of course, they don’t make obvious fixes to improve public transit, and the bike lane “improvements” they put in are mostly textbook “how to kill bicyclists” designs that European countries phased out decades ago.

Here are two classic favorites: concrete barriers that are too close to the curb to allow street sweeping, and adding bike lanes between parallel parking spots and the sidewalks.

They must have realized people started re-routing their trips to avoid stoplights unless they were making right turns, since they’ve also started erecting barriers or adding red arrows to make it impossible to make right turns on red.

Anyway, this wastes time, but it also costs us at least $100 a month on gasoline. Our primary car is an EV.

Anyway, around here, even a small investment in reducing idling (or just cutting funding for traffic quiescence projects) would be equivalent to increasing vehicle fuel economy by something like 20-80%.

[darby_eight]

> Anyway, around here, even a small investment in reducing idling (or just cutting funding for traffic quiescence projects) would be equivalent to increasing vehicle fuel economy by something like 20-80%.

sure, but I'd rather just lobby against cars at that point. Especially in a place like the Bay Area that should be mostly served by public transit and dense housing. Lobbying to micromanage idling just feels like a waste of effort for such a negligible benefit.

[hanszarkov]

I have experienced the same thing 100 plus times