Signals that turn red when a speeding car approaches

[tradephoric]

This is different than a red light camera! 

The idea is if a vehicle is traveling above the speed limit, the signal will automatically turn red before the speeder can make it through the light.  The traffic signal is essentially used as a traffic calming device.   

Here's an example on Porter Street in Washington D.C. (the sign states "Signal turns red when speeding"):
https://maps.google.com/?ll=38.937085,-77.06509&spn=0.001177,0.001725&t=h&z=19&layer=c&cbll=38.937182,-77.065153&panoid=DaBoONjfwPfholq6ws7ulg&cbp=12,128.95,,0,3.22

[hotdogPi]

Does that mean it just skips the yellow?

[1995hoo]

There's one of those on southbound Taylor Run Parkway in Alexandria, Virginia. The speed limit is 25 and I, of course, had to test it out to see if it would really turn red. It did.

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out) and has the same wording as the one the OP cites except it uses the word "red" instead of the red circle icon (Takumi memorably referred to that as "No Turn on Japan" in another context). The traffic light is visible in the distance. You'd have to be going insanely fast to get through before it turns red, fast enough that if you were caught you'd probably face a license suspension. The light is annoying as it's placed mid-block. I assume the city would say it's there to protect pedestrians going to the park on the east side of the street.

http://goo.gl/maps/piMzb

[DaBigE]

This sounds like an accident waiting to happen. About as bad as using STOP signs to curb speeding or uncoordinated signals. Interesting idea, but I'd rather not encourage more unnecessary red lights.

[Big John]

And with narrow sidewalks and no ADA sidewalk ramps either.

[oscar]

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out)
http://goo.gl/maps/piMzb

I think it's an accidental (but all too common) result of deliberately blurring out some details to protect people it catches in embarrassing places or positions.  Blurring out faces of people peeing in the gutter, OK.  Blurring out license plate numbers, I can see as well, to protect people who might be cruising through bad neighborhoods for drugs or hookers, or even more respectable places on the "cheating side of town".  But I can imagine the same process blurring some road signs too.

[Alex4897]

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out)

https://maps.google.com/?ll=38.810486,-77.075229&spn=0.015383,0.033023&t=m&layer=c&cbll=38.810559,-77.075241&panoid=mFMxfX1lNAeJ7B-iZOJihA&cbp=12,208.38,,1,3.04&z=16

Ta-daaa

[1995hoo]

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out)

https://maps.google.com/?ll=38.810486,-77.075229&spn=0.015383,0.033023&t=m&layer=c&cbll=38.810559,-77.075241&panoid=mFMxfX1lNAeJ7B-iZOJihA&cbp=12,208.38,,1,3.04&z=16

Ta-daaa

Yeah, but it's not any more legible in that view (at least, not on my iPad it's not).

[Alex4897]

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out)

https://maps.google.com/?ll=38.810486,-77.075229&spn=0.015383,0.033023&t=m&layer=c&cbll=38.810559,-77.075241&panoid=mFMxfX1lNAeJ7B-iZOJihA&cbp=12,208.38,,1,3.04&z=16

Ta-daaa

Yeah, but it's not any more legible in that view (at least, not on my iPad it's not).

It's a lot more legible on my computer

[hotdogPi]

In the Street View image, the warning sign is to the right (I don't know why it's fuzzed out)

https://maps.google.com/?ll=38.810486,-77.075229&spn=0.015383,0.033023&t=m&layer=c&cbll=38.810559,-77.075241&panoid=mFMxfX1lNAeJ7B-iZOJihA&cbp=12,208.38,,1,3.04&z=16

Ta-daaa

Yeah, but it's not any more legible in that view (at least, not on my iPad it's not).

Once I zoom in to a closer view, it works.

[agentsteel53]

that would only be a reasonable device if it turned back green once I went back below the speed limit.

otherwise, welcome to the sound of screeching brakes, which is really what traffic calming is all about.

[corco]

Is there not a serious personal safety issue here? If im a relatively amateur theft ring, and i see a car i want to rob in the middle of the night, and I see that car  going the speed limit, I can speed up behind them, trigger a light change, and then have my buddy with a gun wait on foot at the intersection, run out, and carjack. This is much easier to pull off when we know exactly where and when the light is going to change.

[Jardine]

Cohort can already press the pedestrian button . . .

[DaBigE]

Cohort can already press the pedestrian button . . .

Pressing button only places a call. Unless you know the exact timing schedule and precisely where in the cycle the signal is, there is no guarantee it will work outside of a peak travel period (and during the peak, you'll obviously have quite a few witnesses). As I understand it, this system changes the signal on a per car basis.

[hbelkins]

Unless the light for cross-street traffic stays red and doesn't turn green, this is an accident waiting to happen. The speeding car is quite likely to blow through the red light that's triggered by his speeding, and if the cross-traffic light turns green, cars sitting there are going to go and get clobbered by the speeding vehicle.

I'd think a speed camera would be a lot less dangerous.

[1995hoo]

Unless the light for cross-street traffic stays red and doesn't turn green, this is an accident waiting to happen. The speeding car is quite likely to blow through the red light that's triggered by his speeding, and if the cross-traffic light turns green, cars sitting there are going to go and get clobbered by the speeding vehicle.

I'd think a speed camera would be a lot less dangerous.

In the example I posted there is no cross street, which makes the light all the more annoying.

[NE2]

Unless the light for cross-street traffic stays red and doesn't turn green, this is an accident waiting to happen. The speeding car is quite likely to blow through the red light that's triggered by his speeding, and if the cross-traffic light turns green, cars sitting there are going to go and get clobbered by the speeding vehicle.

Learn to read.

The traffic light is visible in the distance. You'd have to be going insanely fast to get through before it turns red, fast enough that if you were caught you'd probably face a license suspension.

[froggie]

This sounds like an accident waiting to happen. About as bad as using STOP signs to curb speeding or uncoordinated signals. Interesting idea, but I'd rather not encourage more unnecessary red lights.

As I recall, the DC example was implemented before the city started on their speed camera campaign.  Also, the simple solution (and the way to avoid the "unnecessary red light") is just to not speed.

otherwise, welcome to the sound of screeching brakes, which is really what traffic calming is all about.

Only if you don't know how to properly drive or properly use your brakes.  Admittedly, that's most US drivers.

[DaBigE]

The question I have is how far above the speed limit does one typically have to go to trigger the red light? 2 mph? 5 mph? I routinely see squads going 10 over on routine patrol--I'd LMAO if I saw one of those squads trigger a light.

[Brandon]

This sounds like an accident waiting to happen. About as bad as using STOP signs to curb speeding or uncoordinated signals. Interesting idea, but I'd rather not encourage more unnecessary red lights.

As I recall, the DC example was implemented before the city started on their speed camera campaign.  Also, the simple solution (and the way to avoid the "unnecessary red light") is just to not speed.

A far better solution would be to simply time all the signals for the speed limit.

[hbelkins]

I didn't click the link to see the intersection in question. So sue me.

[1995hoo]

This sounds like an accident waiting to happen. About as bad as using STOP signs to curb speeding or uncoordinated signals. Interesting idea, but I'd rather not encourage more unnecessary red lights.

As I recall, the DC example was implemented before the city started on their speed camera campaign.  Also, the simple solution (and the way to avoid the "unnecessary red light") is just to not speed.

A far better solution would be to simply time all the signals for the speed limit.

I've encountered a number of roads in DC where the signals are timed such that if you do the speed limit, you have to stop at every one of them.

[hotdogPi]

There was a sign (it was white on green!) in Philadelphia that said "signals set for 20 mph".

[agentsteel53]

A far better solution would be to simply time all the signals for the speed limit.

I think Klamath Falls OR still has its main drag timed, complete with signs on every block that state "signals set for 23mph".  [speed limit is 25]

[1995hoo]

There was a sign (it was white on green!) in Philadelphia that said "signals set for 20 mph".

I've seen those sorts of white-on-green signs in many towns in the South, though seldom further north (note I'm not saying they don't exist further north, just that in my observation they seem more common in the South).