New Traffic Signals in London Will Give Pedestrians the Green Light By Default

"Green man authority" will prioritize pedestrians over cars, part of London Mayor Sadiq Khan's plan to increase walking and transit trips.

Shorter waits for pedestrians are part of Transport for London's "walking action plan." Photo: Transport for London
Shorter waits for pedestrians are part of Transport for London's "walking action plan." Photo: Transport for London

The city of London is on a mission to make walking as convenient as possible, using smarter traffic signals that reduce wait times for pedestrians.

For the past few years, Transport for London has been conducting “annual timing reviews” at 1,200 signalized intersections. Last year, the agency adjusted 200 signals to give people the walk sign sooner.

Now TfL wants to take the concept further as part of Mayor Sadiq Khan’s ambitious plan to get Londoners walking more [PDF].

To help meet its goals for “pedestrian time saved,” the agency will begin using smart traffic signals that employ what’s known as “Split Cycle Offset Optimisation Technique” (SCOOT, get it?). These signals, which will be installed at a small number of locations, can detect the number of pedestrians waiting at an intersection and automatically adjust timing to minimize their wait and ensure they have enough time to cross.

At 10 other intersections, TfL wants to use traffic signals to give pedestrians the right-of-way by default. They call it the “green man.” TfL writes:

‘Green man’ authority is a radical technique where the traffic signals show a green signal for pedestrians continuously, until vehicular traffic is detected, at which time the pedestrians are stopped on a red signal, and vehicles are given a green light to proceed. This technique has previously only been used at two locations in London, on bus-only streets in Hounslow and Morden. TfL has identified the next 10 new locations where this approach will be set up, where it would significantly benefit pedestrians, with very little detriment to traffic.

The pedestrian signal improvements are part of the “walking action plan” TfL released earlier this month, which fits into Khan’s goal of increasing daily walking trips from 6 million today to 7 million by 2041.

Hat tip: Systemic Failure

35 thoughts on New Traffic Signals in London Will Give Pedestrians the Green Light By Default

  1. I would love to see this idea take hold more broadly – “smart” signals like this could be a boon to drivers, pedestrians and cyclists.

  2. I’ve been saying this for years. Traffic lights should never go red if there’s nothing crossing. That wastes people’s time and erodes respect for traffic signals. With modern sensor and AI technology we have the ability to make smart signals which only go red if something is crossing, and then for only as long as it takes for the person or vehicle to cross. We can even tweak this and only stop one direction, perhaps even one lane, of traffic at a time while a person is crossing the street.

  3. great points. i can’t imagine how many times i’ve seen 50 cars stop for 25 seconds after just lonely old me finishes crossing.

  4. ‘Green man’ authority is a radical technique where the traffic signals
    show a green signal for pedestrians continuously, until vehicular
    traffic is detected, at which time the pedestrians are stopped on a red
    signal, and vehicles are given a green light to proceed.

    Hopefully I’m missing something, but this sure sounds like priority for cars. So if there’s a continuous stream of car traffic, pedestrians will never get the green light?

  5. Well no. The green for cars has a limited time if pedestrians show up. But if there are no cars the pedestrians don’t have to wait for the lights to cycle and can cross immediately.

  6. Important to remember that London can do this because:

    1. They have a fantastic public transport system, so cars are less important
    2. They added a congestion charge to discourage cars in the city

    The USA has had this technology available for many years, e.g. – but the cost is the issue due to lack of density.

    London also pioneered smart traffic signals, which change to red if vehicles exceed the speed limit, and also work well because everyone learns that to keep moving smoothly along the corridor, you need to drive at or below the speed limit.

    The limited USA viewpoint of flashing beacon crossing, road-diets and refusal to install adequate public transportation is the biggest issue with improving he situation in the USA. DOT’s in the USA focus on zero sum gain solutions.

  7. These signals exist in any intersection where magnetized or weight detection is used for automobiles. It’s truly a matter of flipping a switch to make the green man the default green instead of the automobile green phase.

    It costs the hour per intersection to reprogram. That’s it.

  8. Yes, because minimizing the crossing time for pedestrians and maximizing the speed of motorists should be top priority for any transportation professional.

  9. Yes, I like seeing the weight detection devices – a few are installed where I live and they greatly speed up the flow of traffic.

  10. Three things:
    (1) They are on every automobile lane at intersections to allow cars to affect the cycle.
    (2) You are posting on Streetsblog advocating to ‘speed up the flow of traffic’
    (3) You are posting on Streetsblog advocating to ‘speed up the flow of traffic’

  11. They are not at every intersection – is that what you meant to say?

    As for (2) and (3), yes, of course. Is something wrong with advocating for increased mobility? I don’t see anything gained by having people sit at red lights for no reason. do you?

  12. 1) No

    2) You are not advocating for increased mobility. You are advocating for greater automobile speeds in urban environments.

    The article and conversation is about prioritizing pedestrian traffic. That you log on to champion the same system as a way to ‘speed up the flow of traffic’ speaks volumes.

    *edited directly because I wanted to edit it

  13. 1) Ok, good.

    2) I’m not advocating for great automobile speeds in urban environments. I’m not sure why you think that. In fact, I am a huge proponent of slowing speeds in urban environments. Two things – my comment was about unnecessary stopping/waiting (not speed) and it was in no way limited to urban environments. Moreover, I didn’t log on to champion the idea as a way to speed up the flow of traffic – as is apparent from my comment, I logged on to support the idea and advocate for its wider use. Please take another look at the comments – see what I wrote, not what you imagine I wrote.

  14. Do the weight detection devices detect bicyclists waiting at the light?

    Also, per the flow vs. speeding. Less long stops but more frequent shorter stops will curb speeding between lights.

  15. “Do the weight detection devices detect bicyclists waiting at the light?”

    – I don’t believe so – the ones I’ve seen are placed more in the middle of the lane, and thus not where a typical cyclist would pass. For areas with cycling traffic, cameras may be the better alternative.

    “Also, per the flow vs. speeding. Less long stops but more frequent shorter stops will curb speeding between lights.”

    – Yes, reducing long stops for no benefit is a plus of this type of technology.More frequent stops really depends upon the type of road one is on.

  16. The idea here isn’t just to speed up motorists. Rather, it’s to end unnecessary waiting by any type of user. It’s just dumb to require a motorist (or cyclist or pedestrian) to wait at a red light if nothing is crossing. Point of fact red lights affect cyclists more than any other group. Besides the waiting time, which affects all types of users, neither motorists nor pedestrians incur a significant penalty getting back up to cruising speed. Motorists just have to press a pedal. Pedestrians accelerate pretty much instantly back up to walking speed (and with little energy penalty as the kinetic energy of moving at 3 to 5 mph is relatively low). Cyclists on the other hand take a while to get back up to speed (thus affecting their average speed even after the light goes green). Repeated stops also sap energy and can cause leg cramps.

    So in the end I’m really advocating making things better for all three groups. You can of course still prioritize pedestrians or cyclists over motorists where appropriate via the signals. Here we have one example of that where the signal defaults to green for pedestrians instead of green for motorists.

  17. Actually this works best at medium congestion areas. Probably not good for FiDi, but better for avenues. In SOMA, we’d do better with green wave to help bikes get continuous green lights.

  18. They’re generally magnetized, not weight detection, as I understand it. There are some that are sensitive enough to sense a bicycle, but that is not the norm. Of course, having at least some steel on the bike is essential since aluminum and carbon fiber won’t trigger a magnet.

  19. You don’t need steel to trigger a light, at least for the detectors routinely installed in California. What is important is a large enough loop of metal for an induced eddy current to flow through. Aluminum bike wheels satisfy that. If you have a carbon frame with carbon wheels then your bike might be invisible for the detectors, but the remaining 99.9% of bikes on the roads should be able to trip most sensors.

    And I have not seen a weight based sensor for decades. There are however video camera based sensors now.

  20. It’s essentially a semi-actuated signal with the roadway occupied by cars serve as the minor street and the pedestrian crossing serves as the major street. The green light for vehicles will only be called upon when there is demand and will run for a limited time before the pedestrian phase returns. It’s likely there is not a high demand for vehicle traffic in this area.

  21. It’d good to see London taking this step. While London has some great features for pedestrians, I don’t find it a pedestrian paradise as a Chicagoan living in London.

    First, the zebra crossings, and the respect that all road users, including cyclists, provide pedestrians within the crossing is amazing.

    However, pedestrians walking next to busy roads have to give way (yield) to cars turning off or onto the major road when crossing a minor road. I much prefer the right of way that pedestrians have in such situations in the US. Also, most major roads have phased pedestrian crossings, which means you can be stranded in the island for a few minutes as cars whiz by on both sides.

  22. The problem with this is that most vehicle detection methods are based on magnetic loops.
    If you have a carbon bike, the light will always be in red.
    If you have a metal bike, good luck with the location of the inductive loop..
    And if it is camera operated, most of them discard the borders of the lane, so if you are not in the center.. well, no detection either.
    This makes travelling by ICE vehicle better than bikes.

  23. It is great to know that “Green man authority” will prioritize pedestrians over cars at traffic signals in London. Most cities in the world are trying to install smart traffic signals that can reduce the waiting times for pedestrians when vehicular traffic is light, but go RED quicker for pedestrians when long lines of cars are waiting. But all technologies, including the traffic signals and automobiles, are meant for the convenience of humans, in this case to facilitate the movement of pedestrians, over which vehicular traffic should not have priority. True, the cars are also transporting the humans again, but a car can move fast on the stretch of road further up which is traffic-signals free, whereas pedestrians, particularly the aged ones have to trudge at the same speed. And why do the people who crib about the signal taking time to go green while they are on the wheel, not remind themselves that they too are pedestrians at some point of the day. I think this mentality has come because car drivers look at a pedestrian as a moving object, obstructing their path when they, after all, could have zoomed at 100km+ speed, celebrating diversity under the on-wheel vs. off-wheel syndrome!

    30 years ago, in 1988, I used to walk across the waiting traffic with the swagger of a ‘pedestrian is king’ at the busy crossing on the St. George St. near the main gate of the downtown campus of the University of Toronto, where a version of the ‘Green Man’ was existing. It was for the car-drivers to watch for the stray pedestrian intending to cross, slow down from a distance and stop to let the pedestrian pass. And this crossing was quite well-lit so that the drivers could see a pedestrian trying to cross from a distance. I was a visiting Professor there from Mumbai in India, and was impressed by this arrangement, though most other traffic crossing were conventional in those days in that city. —- Prof. Dr. J.V. Yakhmi

  24. Then one can use the method used in The Netherlands. Add an appropriately located beg button for bicyclists whose bikes don’t trip the inductive sensor. Easy. Or don’t have an all carbon bike. Cheaper!

    Of course there is also the unrelated fact that ICE vehicles are going to go away because their owners will realize the advantages of going all electric in a decade or two. Doesn’t affect signals though.

  25. How utterly stupid.

    It would be far more sensible to synchronize and meter traffic lights on the primary north/south and east/west auto routes to allow vehicles to move at a steady 20 to 30 MPH. Waves of pedestrians and vehicles can then both cross intermittently.

    Constant stopping and starting by vehicles causes *more* exhaust.

    Unsynchronized lights cause motorists to make mad dashes from stoplight to stoplight, in a vain attempt to catch them, rather than just calmly following the 20-30 MPH synchronized pace.

  26. Yeah, no sorry but giving pedestrian priority should always be the *priority* because making a car less convinient is going to discurage people from using it and that always help, less car, less pollution…

  27. Except the vehicles will still be there *anyway*, because they *have to be*, like buses and commercial vehicles. Meanwhile, stop-and-go accelerating and then rapidly decelerating vehicles pollute *far more* than vehicles doing a steady 25 MPH pace.

  28. for less dense ped areas, which are most places, pedestrians might be best off with reduced speed limits, enforcement, and enhanced penalties if a careless or speeding motorist actually injures or kills someone.

  29. It shouldn’t matter how many pedestrians are waiting. Even at seldom used crossings this would invite more pedestrians if it wasn’t crowd based. You can’t get more people walking if the signals are already timed to only shorten your wait if there’s a lot of you. Seldom used crossings would never get any better and peds would become frustrated at the wait times and find other means.

  30. One good reason to stick to hiten steel!
    Still, they should extend the sensor to all the surface + beg button.

    As for ICE going away.. well, yes, but it will take quite a bit of time.

  31. I ha
    “We have to let the cars go fast because they pollute more if we slow them down!

    No. They pollute the least when we don’t drive them. Anytime you make driving easier, more people will drive, and you get more pollution. Adding another car to the street creates far more pollution than any reduction from speeding traffic flow. That argument is trash. Please stop pulling it out and throwing it around the kitchen like a misbehaving dog.

  32. And when they stop-start-stop-start, they pollute more. Simple as that.

    You can have them drive at a slow but steady pace by synchronizing traffic lights. Without synchronization, they will make mad dashes in order to make the lights. This is simple fact.

  33. When you prioritize vehicle traffic, you get more vehicles.
    Adding more vehicles will add more pollution.

    Drivers make mad dashes to stop lights regardless of the timing, especially when you design the street in a way that communicates to a driver that they are the priority. An environment that prioritizes pedestrians tells drivers that they are the guest and must watch out for others leads them to drive more safely.

    What you are calling for has been done for decades in the US. The results are horrendous.

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