Friday, August 13, 2010

Pedestrian ahead!

Speed and proximity. They are the two factors that lead to both pedestrian anxiety about and actual bike v. pedestrian conflict. If you are walking and a bike whizzes right by your shoulder, it's disconcerting and unpleasant. A person on foot is highly maneuverable (no momentum) and may dart left or right or stop suddenly without warning. So, there is a high risk of a bad outcome.

People on bikes are bigger than pedestrians -- bike plus biker plus gear -- and less forgiving. And, bikes are faster. Keep in mind that the squared variable in mv2 is v, velocity. So, bikes have a special obligation to watch out for and take care of pedestrians when sharing the road (as in crosswalks) or shared paths.

I've been thinking about this a lot recently because, as previously noted, I've been riding the paths along the Charles River to accommodate camp drop-off for Princess NS&S. (I really did get stung, I didn't really give up the bucolic route!) I'm following two simple rules that I encourage others to follow:

  1. Give a wide berth when passing a pedestrian, particularly from behind
  2. If you can't give a wide berth, slow to just faster than the person you're passing

What's a wide berth? Depends on the speed, but at least three feet and ideally five feels right.

What about yelling "On the right/left"? If you need to warn the person you're passing that you're passing, you're going too fast or coming too close. Plus, in my experience, yelling something just heightens the risk that the person will do something unpredictable. (Does he want me to move left? Is he coming on my left?) And, it's just downright annoying.

When I'm riding in traffic and a driver honks just to warn me that he's behind me, it's aggravating. I'm in traffic. I know cars are going to pass, I don't need to be reminded. And, if it's a dangerous situation, slow down until you have room to pass slowly. I feel the same way as a pedestrian among bikers. Get by me safely ... and silently ... or cool your jets.

Finally, the anxiety and risk created by a high speed differential between bikers and pedestrians makes most shared paths a lousy place for faster riders. We should stick to the streets or just take our time.


dr2chase said...

I would recommend against "on your right". Given that people may or may not be wearing iPods, and are creatures of habit, there's a good chance that they'll hear "on your jkashdfkjhew" and step to the right, assuming you meant left.

The one time I really almost hit a jogger, "on your right" figured into it.

Usually, especially after the on-your-right experience, I either pass very wide, or just wait. If I'm really impatient, I've got the option of passing on the grass (tires of unusual width, on the bike of unusual size).

Michael Pahre said...

I thought that cyclists on bike paths were legally required in Massachusetts to signal audibly that they were approaching to pass a pedestrian. The sound can be voice or a bell, but state law specifically forbids one of those noisy honking horns (or a siren or whistle).

As a pedestrian/runner who often runs along the Charles, and a bicycle commuter, I get this from both sides. And I can tell you that, as a pedestrian, I always want the warning that a cyclist is about to overtake me.

Anonymous said...

I think you should give up on this special obligation nonsense. It's rules of the road. If you're a cyclist and your vulnerable to cars, you should be exceptionally careful. If you're a pedestrian and sharing a bike path, you shouldn't be making any sudden moves without looking behind you. The idea that the more vulnerable can be less careful just because they are more vulnerable and others have "special obligations" towards them is a recipe for disaster. Bicyclists and drivers have an obligation to not do anything to cause ANYONE to end up in an accident. To bring up crossswalks is superfluous and paints the wrong picture in this context. Neither bikes nore cars should be entering one if a pedestrian is crossing. That's not a special obligation. That's same roads, same rules.

Sean Roche said...

I continue to be puzzled how asking a bicyclist to take special care around pedestrians or a car driver to take special care around bicyclists translates into lowering the need for pedestrians in the first case and bicyclists in the second place to be vigilant. It's not a zero-sum game.

Bicyclists should ride the streets with the knowledge that a mistake by the rider or a driver can lead to serious injury or death. Sad to say, but true.

And, a pedestrian on a shared path should beware of bikes and not make sudden moves.

On top of that, because they are faster and can cause more damage (in the case of a car much more damage), the car on the road and the the cyclist on the path should look out for and avoid potential conflicts.

As for bikes and crosswalks, I'm pretty sure bikes and cars can pass when it's clear. I've seen too many cyclists, though pass oh-so-close behind pedestrians in a crosswalk. In any case, your broader point is well-taken. It's part of the special obligation -- whoops, I said it again -- for cars and cyclists to be super-duper abide the law. Notwithstanding, pedestrians should also be cautious because you never know ...

Sean Roche said...


By my reading, the audible signal rule only applies to riding on sidewalks, not mixed-use paths (MGL ch. 85, sec. 11b). But, I'm not absolutely certain on that point.

If it applies only to sidewalks, that one's easy. Adults really shouldn't be riding on the sidewalk if there are pedestrians around. Get off and dismount, and then call your local public official and ask for on-street bike accommodations in the area.

If it does apply to mixed-use paths like those along the Charles, it's a bad rule. Among other things, it encourages bikers to think that all they have to do is signal.

Anonymous said...

As a pedestrian, I love when cyclists use a cheerful-sounding bell to signal their approach. The sound carries, so they can do it from well-back, and it doesn't involve bellowing or the potential of misunderstanding what someone said.

Anonymous said...

Look, maybe you have alzheimers, you tend to be puzzled by a lot of things, although usually only when it's convenient. You've blogged earlier that a bicyclist should be able to make a mistake and not have it be life threatening. Your tone as well as words in earlier posts CLEARLY shifted the burden of avoiding an accident onto the driver because of your supposed "special obligation". That lifted the burden from the cyclist. In other posts you've compared an abusive relationship to a rational desire on the part of a bicyclist to more amiably share the road and take responsibility. That comparison was so absurd it wasn't even worth commenting on. Funny, you didn't even comment on the recent death of a young woman on Comm. Ave who wasn't wearing her helmet and was probably going too fast. A terrible tragedy. So far it's ruled as an accident. I'd hate to think it wasn't mentioned because it doesn't fit into your blame the driver scenario. You say super-duper abide the law now, but it's hard to forget your tone and absurd views in other posts. Both sides have to be careful and take responsibility. Cyclists being careful around pedestrians is a good thing. Your view of a special obligation which was previously used to shift the responsibility regardless of action is not good. I've no doubt you'll be using your "I'm puzzled" reply again.

Sean Roche said...

Wishing for a world where a rider can make a mistake and not have it be fatal is not the same as saying that rider's ought to make mistakes. Again, it's not zero-sum. If riders and drivers are extra vigilant, the odds of a bad outcome go down. I have written that there is a cost of putting the entire responsibility for vigilance on the rider, but that's a far cry from saying that riders ought to be carefree and ride without regard for their own safety.

As for the young woman who died in Brighton. I just learned about it yesterday. I don't typically blog about what happens outside Newton, maybe I should. But, I am planning to post something about this accident, to the effect that reckless riding is going to get you killed.

Anonymous said...

Bells need to be made mandatory.

The noise is pleasant and unique to bikes, everybody knows what they mean.
Shouting anything is rude and could lead to confusion (person stepping left when hearing the word left).

I completely agree that you should only pass pedestrians at a just slightly faster speed than they are moving.

dr2chase said...


I guess I haven't had good luck with the bell or the on-your-left; most of the time, whenever I do either, the ped about jumps out of their skin -- or, they are wearing headphones, and don't hear me at all. But I do know that on-your-right is a non-standard and risky thing to say. So, since I don't like to give people heart attacks, I just pass really wide. And dogs and kids, you have to pass really wide anyway, because you never know -- the dog can kill you, and it would be pretty awful to hit someone's kid.

Most of the time, nowadays, I use the bell when I'm approaching a crowd of kids who look like they are horsing around (or about to be).

Maybe I'm doing bell the too close.

I really don't get the anons with their whole special obligation nonsense. It's easy, do it by the numbers. Using pedestrians killed as a proxy for "danger", and assuming a 0.5 to 1% ride share for bicycle, we can infer from mortality stats that cars are 15-30 times as dangerous as bicycles, given current habits of use (car are to bicycles, as drunk drivers are to sober drivers, in terms of chances of hurting someone else.) Everyone has an obligation not to hurt other people, and cars are failing spectacularly, compared to bicycles. It is not a "special" obligation, it is an unmet, failed obligation on the parts of drivers (as a population, not one-by-one). Part of the problem is the inane focus on laws of the road, to the exclusion of laws of physics. Bicyclists get their safety-for-others from physics, which (clearly) works better than laws of the road (the advantage here is that we can forget to obey laws of the road, but laws of physics are always obeyed). And of course, pedestrians do best of all on physics, because they are so slow, and bring the least energy and momentum to any collision.

Anonymous said...

You must be running for office or something. You're not retracting what you're saying but you're twisting it. You didnt' really say anything about the cost of putting all the responsibility on the rider. Although that it could be an odd twist on what you said about the onus of extra vigilance and special obligation going to the driver of the car because he could do more damage. Look, you know what you said, you want to twist it to something different because it doesn't now suit your purpose... have at it. Others can reread your blog if they care. I remember you being all over the bicyclist who was hit by the bus. Mostly all over the bus driver, proving your previous point. I don't think that happened in Newton. People forget. Generally it doesn't come back up until someone runs for office.