Greater Greater Washington

Instead of tickets, turn lights red for speeders

Opponents of speed cameras often insist that they don't want drivers to speed—what they object to is the revenue-raising function of the cameras and their invasion of privacy. There may be a way to give these critics what they say they want, at least on some roads, while curbing excess speed more effectively.

Photo from FHWA.

How about wiring radars to turn the next traffic light red whenever a speeder passes? Instead of getting a ticket in the mail, a speeder would just get a red light. With the right settings, this would slow down all speeders—including those who speed by less than 12 mph.

Traffic safety experts I spoke with could not point me to any experience with such a system, so it will take trial and error to work out the bugs and optimize the design.

Speeders' behavior is more likely to change if they understand why they got the red light, but if drivers get that message too soon, they might speed up more to beat the light instead.

If a light turns green and then a speeder fairly quickly shows up, turning it red again, there might be pedestrians in the parallel crosswalk. They'll need time to finish crossing, which would mean a 4-way red period. However, these will have to be minimal so that drivers are not overly tempted to run red lights.

And how would this work on multi-lane roads when one speeder might stop traffic for many other law-abiding drivers? Signals always give some unnecessary red intervals—they can't perfectly match changing traffic volumes through the day—but the red lights shouldn't excessively interfere with vehicle movement. The first experiments should probably be on narrow roads with relatively light auto traffic.

There shouldn't be legal obstacles. Radar-actuated traffic signals are approved by the Federal Highway Administration, and state laws that limit the placement of speed cameras do not apply to them. Some cities (including DC on parts of 16th Street) already limit speed with traffic signals by synchronizing closely-spaced lights so that drivers who exceed the limit hit a red.

How and where might this strategy work best? And will objections to automated speed limit enforcement diminish when the radar system no longer raises revenue from drivers?

Ben Ross was president of the Action Committee for Transit for 15 years. His new book about the politics of urbanism and transit, Dead End: Suburban Sprawl and the Rebirth of American Urbanism, is published by Oxford University Press. 


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Honestly, I've seen plenty of people gun it to the next red light around here. I like the idea, but I think there would be too much collateral effect to pedestrians and other drivers.

by m2fc on Apr 16, 2013 12:57 pm • linkreport

I think there's one of these on Wilson(?) in Arlington.

by JoeSchmoe06 on Apr 16, 2013 12:59 pm • linkreport

There's already one of these in Arlington on Wilson Blvd.

by Sam on Apr 16, 2013 1:00 pm • linkreport

Why not both?

by drumz on Apr 16, 2013 1:04 pm • linkreport

Why not time a set of lights to the speed limit. Speeding will only waste your gas, won't affect non speeders, light intervals or pedestrians.

by Patrick on Apr 16, 2013 1:06 pm • linkreport

And if they speed twice, then program the system to recognize their EZ-pass transponder so every light is red for the rest of the day. Third offenders--the rest of the week. Fourth offenders: All drive-in windows turn red.

by JimT on Apr 16, 2013 1:07 pm • linkreport

There has been one of these on Porter St in Cleveland Park, between Reno Rd and Connecticut. Been there for atleast 11 or 12 years. There is a radar gun and a display that tells you how fast you are going. If you exceed the speed limit, it triggers the light just down the street to turn red.

by CPark on Apr 16, 2013 1:07 pm • linkreport

There's one in Cleveland Park as well.

by MoCo on Apr 16, 2013 1:08 pm • linkreport

I believe there's one of these on Porter between Reno and Connecticut. The light is also at a crosswalk. Based on my own anecdotal experience, it seems to work fairly well.

by rccr on Apr 16, 2013 1:08 pm • linkreport

I suggest a composite approach that combines multiple sanctions including fines, inconvenience, and public shaming. First, when the radar detects a speeder, a moderately priced ticket should be generated in the usual way. Second, the next (nearby) traffic light should be turned red to remove the benefits of speeding. Last, there should be a jumbotron TV screen showing for all to see the offending car and driver that inconvenienced everyone else. I doubt there would many repeat offenders.

by Steve Amter on Apr 16, 2013 1:09 pm • linkreport

There are, or at least used to be, these types of lights on a stretch of the Herndon Parkway between Elden and Van Buren.

I'm not sure jurisdictions would go for this, though. It's a revenue stream for them. They don't necessarily want red light violations to stop.

by jh on Apr 16, 2013 1:12 pm • linkreport

As CPark says, there is one of these on Porter Street between Reno and Connecticut. One problem I've seen with that particular set-up is that some drivers have found a work-around... they speed even faster so that they make it through the light before it turns red, trapping everyone behind them at the light while they suffer no real consequence. I'd say that these people only account for a handful of speeders on Porter, and the majority of the speeders do get trapped at the red light. But, those who speed even more to avoid the trap end up causing what is perhaps a greater public safety concern by speeding more than they otherwise would. I imagine this issue could be solved easily by increasing the space between the radar and stoplight, but I'm certainly not a traffic engineer.

by Jeff on Apr 16, 2013 1:18 pm • linkreport

Traffic safety experts I spoke with could not point me to any experience with such a system

Maybe not this exact system, but there are plenty of roads with green waves, i.e. zones where multiple traffic lights are timed to allow passage through several intersections. Many of them are time exactly so that if you speed, you can not get through. It does not work. There are always people speeding, who are then forced to stop, and then force the non-speeders to stop.

by Jasper on Apr 16, 2013 1:18 pm • linkreport

Cool idea that works in some places it seems. In places with more significant traffic it would probably lead to too many backups. In the two examples people have pointed out here, the traffic lights aren't at an intersection - they are in the middle of a long downhill stretch to prevent people from just cruising too fast through those places.

Along 15th St NW in DC, the lights are timed so that if you drive about 25 the lights turn green as you get to them - drive faster and you end up hitting reds. I had to explain this to a cab driver once.

by MLD on Apr 16, 2013 1:19 pm • linkreport

Works for me!

by Capt. Hilts on Apr 16, 2013 1:53 pm • linkreport

There are a couple in Alexandria. One on King St east of Janneys Lane and one on W Taylor Run Parkway, near Angel Park. Going south on W Taylor Run, it's easy to spot the induction loop which triggers the red, so one can slow to below 25 mph just at the loop.

by Jim on Apr 16, 2013 2:06 pm • linkreport

There's another in Alexandria: W Glebe and Old Dominion Rd. Out-of-state drivers trigger this one all the time.

by Matt on Apr 16, 2013 2:18 pm • linkreport

"Traffic safety experts I spoke with could not point me to any experience with such a system, "

WTF?!?! I don't know in the US (I don't drive here), but in Europe these systems are everywhere. Nice "experts" that you found to talk to!

by Miguel on Apr 16, 2013 2:21 pm • linkreport

"Traffic safety experts I spoke with could not point me to any experience with such a system, so it will take trial and error to work out the bugs and optimize the design. "


They were doing that on King Street in Alexandria and on Elden Street in Herndon 15 years ago. The speed limit was 25 and there were signs that said "signal turns red when speeding" and it worked.

Why is this now a big deal?

by ceefer66 on Apr 16, 2013 2:23 pm • linkreport

I don't think what people are referring to in the comments are lights that turn red for speeders. How would anyone know who was speeding change wasn't a coincidence unless someone stood with a radar gun all afternoon and watched the light change? You would have to know the timing of the light, etc. What does exist are lights that have weight sensors that when cars approach, they turn the lights red for the other traffic to let them through. It is to keep lights green for as long as possible for heavily traveled roads that only turn red when a car approaches (hits the weight sensor) on a less traveled cross street. Personally, I would like more of those because there are many times when you are stuck at a red light when there are NO cars on the cross street. Why do I have to stop if there is no cross traffic? Keep the light green until there are cars weighting on the cross street to cross.

by adelphi_sky on Apr 16, 2013 2:27 pm • linkreport

Another nice point about the one in Cleveland Park is that a pedestrian can walk up and push the button to cross Porter and actually get a walk signal within a few seconds -- even if the signal for cars going down Porter has turned red before the button is pushed.

by Eileen on Apr 16, 2013 2:30 pm • linkreport

I'm not entirely sure if I get what your comment is hitting at, so forgive me if this is off-point. The reason I know that the light on Porter Street turns red due to speeding is because there is a sign that informs drivers that the light will turn red for speeders:,-77.065036&spn=0.005633,0.013078&t=h&z=17&layer=c&cbll=38.937179,-77.065143&panoid=DaBoONjfwPfholq6ws7ulg&cbp=12,118.96,,0,13.98

by Jeff on Apr 16, 2013 2:41 pm • linkreport


Thanks. That's pretty cool. I have never seen one of those.

by adelphi_sky on Apr 16, 2013 2:46 pm • linkreport


In addition to Jeff's evidence, I can testify that the one in Herndon certainly turned red every time I tested it.

by jh on Apr 16, 2013 3:10 pm • linkreport

Why not time a set of lights to the speed limit. Speeding will only waste your gas, won't affect non speeders, light intervals or pedestrians.

Because the more complex the road network, the more difficult it is to do so. I've you're in Greenbelt "timing the lights" might be feasible. In NW DC it's a pipe dream.

by oboe on Apr 16, 2013 3:13 pm • linkreport

I think tickets are good. As a pedestrian and biker and have gotten used to the traffic light patterns at many intersections. For example, I know that the northbound lane of 13th St NW gets a left turn arrow after the solid green at Military Road. So if I'm going south and no cars are going north then I'll go straight through if it just turned red.

If these red light radars are used then I would like to see an extra long pause between the light turning red and the other light turning green/the cross walk telling people to cross. I'm imagining pedestrians starting the cross and the guy who triggered the red light blowing it.

by TakomaNick on Apr 16, 2013 3:51 pm • linkreport

Makes sense in lighter traffic areas.

Not sure how this would work in congested rural areas where at least in theory our lights are timed.

Wouldn't this in theory end up breaking that timing cycle in all directions, having a domino effect well beyond that one intersection?

by Hillman on Apr 16, 2013 4:07 pm • linkreport

Meant urban, not rural areas....

by Hillman on Apr 16, 2013 4:08 pm • linkreport

I had no idea so many of these were in the area. Guess I haven't driven on any of those streets yet.


Agreed on the urban areas thing. I never speed driving around here because I know I will inevitably hit a timed signal that is red, or as MLD notes, miss the timing because I am speeding.

These would be very helpful out in the suburbs where large arterial roads encourage speeding - like Veirs Mill, US50 in VA, University Boulevard, etc.

by Nick on Apr 16, 2013 4:27 pm • linkreport

I haven't been down that way in a while, but the one on West Glebe in Alexandria used to be disastrously bad. (And adelphi_sky, I know it worked that way because Alexandria posted signs informing drivers that speeding triggered the light). The radar guns pointed in both directions, and eastbound drivers were punished with a red light when there were westbound speeders and vice-versa. Since it's a busy arterial road with a 25 mph speed limit, there was basically always a car that would trigger it. Which means the intersection functioned as a four-way stop. Or more accurately, a four-way stop with a ~30 second dwell time. I also witnessed a lot of red-light running there by the drivers who triggered the signal change. So on balance it mostly just wasted a lot of gas and a lot of drivers' time.

Perhaps with a better implementation it could have served a useful purpose. But Alexandria could have saved a lot of money and frustration by just putting in 3-way stop signs there, plus maybe some raised crosswalks.

by c5karl on Apr 16, 2013 4:50 pm • linkreport

I wouldn't worry about people gunning it. The "sensors" would be placed at a location that, if triggered, would not provide the driver the opportunity to even come close to making it. If you are speeding 30 feet from the light, that won't trigger it (maybe it triggers the next block, though). These triggers are far enough away that you'd basically have to accelerate to 100 MPH in about 3 seconds to make any attempt at "gunning it." (No, I didn't actually do any math there. I made up the 100 MPH and 3 seconds. The point is simply that "gunning it" doesn't apply - or doesn't have to apply - to these lights.)

by jh on Apr 16, 2013 4:53 pm • linkreport

Yes, the sensors are quite a ways down the road from the light - on Porter the sensor is 500 feet from the traffic signal it controls.

by MLD on Apr 16, 2013 4:57 pm • linkreport

Here's the sign warning that speeders get red lights on Porter Street:

by Mike on Apr 16, 2013 5:30 pm • linkreport

In the City of Los Angeles there were a number of traffic signals that operated as "rest in red" 20 years ago, not sure if they still do...

One on Bevely Glen Bl down hill at the mid-point of the canyon and another on Sunset Blvd adjacent to UCLA. The there were paired inductive loop detectors in the pavement in the approach lanes some distance in advance of the intersection (something at little longer than the breaking distance at the speed limit). Primarily operating off-peak hours, the traffic signal is normally red, unless you were approaching the intersection at the speed limit or less then would change to green as long as the side street (or crossing ped signal) wasn't already green.

A number of cities and towns use this type of operation overnight instead of turning all their signals on to flashing operation.

The one on Porter street in DC "drops to red" on the down hill approach if vehicle is above a certain speed way up the hill . Again paired loop detectors allow the signal controller to know that an approaching vehicle is coming too fast and signal changes to red. (That one you can requestion the signal timing and sequence plan from DDOT)

You don't need radar to measure the speed...

by Some Ideas on Apr 16, 2013 6:12 pm • linkreport

The entirety of the main drag (a little over 2 miles) in my hometown has lights timed so that, once you get one red, if you drive the speed limit the rest of the way, you'll get all greens (since there are at least 7 lights in this stretch, it's a major benefit). IF YOU KNOW ABOUT IT (my grandfather told me about it all the time when I was wee and I remembered it when I became a driver), it's AWESOME. But many drivers seem to not know or care. Perhaps a sign under the speed limit signs saying "green lights if you obey speed limit" would help, but people generally race between lights and then sit at reds, oblivious to the fact that if they had slowed down they wouldn't be stopping. What sucks for those of us who know about this is that we get beeped, flashed, and passed in the turning lane for having the audacity to drive the speed limit. 35 is WAY too slow on a 3-lane road through a residential community, and all.

by Ms. D on Apr 16, 2013 8:56 pm • linkreport

16th Street southbound from the DC line to Mt Pleasant is already timed as a green wave for cars.

Below is a link to the tiny sign that indicates the same (it's the sixth sign down not counting the traffic light). I think this sign is an excellent example of why MUTCD exists. Left to their own devices, too many sign shops would print 6 point font signs.,-77.03639&spn=0.030988,0.052314&sll=38.003385,-79.420925&sspn=8.039092,13.392334&hnear=Washington,+District+of+Columbia&t=m&z=15&layer=c&cbll=38.99067,-77.036374&panoid=LQniZOXA7jI_9-iGpT7Z0Q&cbp=12,200,,0,-2.58

by Paul on Apr 16, 2013 10:42 pm • linkreport

Let me get this straight. One car speeding down the road causes the next light to turn red, thereby forcing everyone else on the road, including non-speeders, to stop.

Okay, while we are at it, I also propose that if someone breaks into my house, I think all of the homeowners on my block should all have to chip in to cover the deductible and everyone's insurance company, not just mine, should cover the rest of the cost to repair my house and replace the items stolen.

People who object to the revenue raising aspect of speed cameras can solve their problem in one simple step. Don't speed.

by Ken on Apr 17, 2013 8:24 am • linkreport


I tend to agree. I have so far paid $0 in speed camera/red light tickets. Very simple reason, I don't speed (at least more than 5 over at any point) and I don't run red lights.

by Kyle-W on Apr 17, 2013 9:45 am • linkreport


by Vince on Apr 17, 2013 9:59 am • linkreport

"Along 15th St NW in DC, the lights are timed so that if you drive about 25 the lights turn green as you get to them - drive faster and you end up hitting reds. I had to explain this to a cab driver once."

Pretty sure H St NE westbound works the same way. Cruise around 25 or so and you should get all green from the Starburst to the bridge. Have only tried this a few times, but seems to work consistently.

by wylie coyote on Apr 17, 2013 10:09 am • linkreport

Ooops. accidentally erased my post:

Cleveland park's light only works if one's rate of speeding is slower than something like 78mpg. Above that, and one can zip through the yellow light. I don't do that, because I drive a bicycle, but I've seen others give it a shot.

by Vince on Apr 17, 2013 10:56 am • linkreport

The Town of Herndon uses road sensors to turn lights red for speeders on Herndon Parkway.

by dcseain on Apr 18, 2013 11:58 am • linkreport

I like that we are thinking of all the ideas, but this one could do real damage. Pulling out on North Cap the other morning a driver from Maryland ran the red light going well above the speed limit and nearly took out the back end of my Jeep.

Also I am not sure I agree with the notion that a driver's behavior will change if they know the light will turn red when they are speeding. In fact, I think more people will speed up for the yellow.

Has anyone found evidence that this works in a city/urban setting. The burbs makes for a terrible comparison (fewer peds/bikes).

by Andy on Apr 20, 2013 8:48 am • linkreport

Currently, there are a lot of roads where I live where the signals are set so that you get stuck at every single red light if you go the speed limit (College Park, I'm looking at you!). Essentially you're punished for doing the right thing. But no surprise there - it's a way of pushing people to speed so the government can issue a ticket.

I'd like to see traffic signals synchronized with the speed limit and shorter. There would be less incentive for people to speed. It's not all about punishing people; how about some rewards for being a good little citizen?

by Crabby on Apr 24, 2013 3:13 pm • linkreport

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