Tuesday, July 6, 2010

Perils of the Pedestrian Push Button

I’ve been thinking a lot lately about pedestrian push buttons. Okay, full disclosure? I’ve been thinking about pedestrian push buttons because a few weeks ago a police officer yelled at me for crossing against the “don’t walk” sign.

Yes, yes, I know this is bad behavior for a pedestrian advocate. But here’s the thing: I arrived at the intersection a mere second before the traffic light changed to green. Just as I reached for the button— *click* green light—and there I was stuck waiting through a full signal cycle, even though there was more than enough time for me to safely cross.

I feel there are other walkers out there who can empathize with this situation. They might even be asking, like me, “Why? WHY? must I push the crosswalk button every time or be stuck languishing at the edge of the sidewalk while the vehicles next to me whisk gleefully through the intersection?”
Actually, I know the answer to that question. When traffic signals include a walk cycle, they are timed to allow a “typical” pedestrian to make it safely across the street (a typical pedestrian walks at a speed of 3-3.5 feet per second). If there are no pedestrians around the green cycle can be much shorter, because vehicles move through the intersection at a much more rapid pace. Thus, to keep traffic speeding along, at many intersections engineers only turn on the longer walk cycle when a pedestrian indicates their presence by pushing a button.

On the surface this seems reasonable, but a closer look reveals a vehicular bias. First, most modern traffic signals extend green times when they detect additional vehicles waiting to move through an intersection. Yet, there is no such extension for pedestrians—and at many intersections pushing a crosswalk button after the green cycle has begun won’t activate the “walk” signal even if there would be adequate time for a pedestrian to cross without extending the cycle length.

Second, there seems to be (and I admit I haven’t confirmed this scientifically) an over-reliance on pedestrian push buttons. As described in the Florida DOT handbook on pedestrian design,

Designers are cautioned to not use actuated push buttons on crossings where there is always adequate time to phase a pedestrian. Pedestrians should not be required to push buttons when it is not essential for adding time. Many pedestrians do not push buttons. It is the engineer’s job to give them a WALK signal whenever possible. Otherwise they give up on these information systems, and fail to use them, even when they have a specific purpose. "

I appreciate the desire for efficient intersection design. But with a few tweaks--the elimination of unnecessary push buttons, the extension of green times for late-arriving pedestrians--intersections can be made efficient for everyone, not just vehiclesMaybe then I'll stop getting in trouble for crossing against the "don't walk" sign...


  1. I like your blog. I hate the buttons. They're useful when there's no car around to trigger the signal to change, but I think the light should automatically switch to walk whenever it switches to green for cars. And I'll go further and say that I think the way the buttons are now used, as well as the general bias in favor of motor vehicles, is a denial of our right to equal protection and an unconstitutional burden on the right to walk. Walking is a fundamental right, just like speech, privacy and other recognized rights. Driving isn't a right and it just infuriates me that people walking can be punished based on policies and practices that unconstitutionally burden those rights and that are biased on favor of people driving, who are taking advantage of a privilege, not exercising a right.

  2. I don't think that's particularly bad behavior from a pedestrian advocate, IMHO. These buttons are awful. When they're not functionally inhibiting pedestrians they're insulting them.

    Here in SF a bunch have gone up in recent years. Almost all are placebos, or else prompt an audio message for the visually impaired. But even these make me suspicious. As you point out, cars are sensed and waved through with as little inconvenience as possible. Pedestrians are made to feel we need to ask cars for permission to cross.

  3. Thanks for making me feel better about my subversive behavior. I'm not a big button fan, but I can see the logic of using them occasionally. However, a placebo makes no sense--why torment us that way? I like how the City of Ventura does it: every time you push the button you get a "beep" to let you know it has been activated. At least then you aren't stuck at the intersection wondering whether or not you'll ever get across...

  4. Hi, I'm glad I found your blog. I appreciate your passion for human feet being put to good use! More importantly little feet. Kids could improve their health so much if they walked more....I'll keep reading ya :)

  5. Great blog to stumble upon.
    I design these devices for a Canadian manufacturer and this feedback is invaluable.
    I agree that the traffic planning focuses (too heavily??) in favour of vehicular traffic. This needs to change especially if we want to get more people 'out of their cars'.
    Perhaps we need to lobby for autonomous sidewalk pedestrian presence detection in place of or as an aid to Pedestrian Push buttons (which are essential for Accessible actuators for handicapped individuals) just like left turn vehicle lane occupancy sensors which bring up turning phases.

  6. Simmer down Eileen, wouldn't it be annoying to be stuck at a red light with a walk signal when there is nobody there to walk? Traffic lights are smarter now, and most have sensors that recognize when there is no car at a particular intersection, so it won't switch to that particular light. People are too small, and aren't always in the same exact spot for sensors to be financially viable to pick up pedestrians.

    Pushing a button isn't a big deal, I live in the city and do it several times a day. Suck it up.

  7. Hi Tom--
    Well, but it's equally annoying to be stuck--as I was yesterday--waiting through an entire signal cycle because I was a half-second too late in my button pushing. Signals can be pretty sophisticated, perhaps we make them actuated (e.g. push-button activated) only at during certain times when pedestrian aren't likely to be around?