Log in

Previous Entry | Next Entry

I was doing some research to learn more about what vehicular cycling really means. (Hard-core nutcases who want to sabotage all alternatives and drive off casual bikers? People giving reasonable suggestoins for how to be safe under current conditions?)

seems reasonable. Of major advocates, John Forester (a founder, author of Effective Cycling) seems purist, opposing bike facilities, advocating full road biking... if you can sustain 18 mph, and go away if you can't. John Allen, not mentioned here, seems more flexible, criticizing Cambridge and Somerville cyclepaths for poor design but not opposed to the idea. Hiles picks on Foresters statistics, legitimately, though says good things about the book at the end. My interest has moved on, though:


are about accident types and risks. A vehicular claim, which I slipped into my previous post, is that 'overtaking' accidents are a small proportion of all accidents. Hiles cites evidence saying "yes, but those are the *deadliest* of all accidents" -- in Cross-Fischer, 25% of fatal car-bike crashes were being run down from behind by a car that didn't see you. Those tend to happen at night on dark 'rural' roads to bicyclists without lights, though.

Hiles mentions lots of confounding factors: rural roads have fewer opportunities for other kinds of accidents; overtaking accidents (including sideswipes, "saw bike but misjudged distance") being rare might be due to bicyclists taking steps to minimize the risk; non-fatal accidents leading to brain damage can be about as tragic as simple death. Also in the US lots of bike use and thus accidents are by children, whose accidents are overwhelmingly of the biker error, riding out of driveways, etc. type, while they hardly ever get to bike down rural roads at night.

Forester may be close to the mark in saying that cars play a part in
only 12 percent of cycling crashes. Studies of emergency room-treated
bicycle injuries indicate that motor vehicles are involved in 9.4 or 18
percent of these cases

It does not follow, though, that we should only devote 12 percent of our
bike safety concern to car-bike crashes. A Seattle, Washington, study
found that half of all serious bike injuries involve motor vehicles.
What's more, 82 to 96 percent of bike-related deaths involve motor

The United Kingdom Department of Transport has provided a more dramatic
illustration of the difference speed makes. The department determined
that when pedestrians are struck by cars traveling at 20 mph, only about
five percent are killed and most injuries are slight, with 30 percent of
the walkers left virtually unscathed. At 30 mph, though, 45 percent are
killed and many seriously injured. Cars zipping along at 40 mph kill 85
percent of the pedestrians they strike (Bicycle Federation of America,

Side note: helmet probably won't protect you at 40 mph. As noted, MA residential streets default to 30 mph, nearly LD50. Dutch streets without separate bike lanes default to 18 mph.
Side note: someone in my reading, I saw the comment "Using the streets that cyclists fought so hard to get paved BEFORE cars were the norm", which reminded me of what I'd learned, that our city streets were first paved at the demand of bicyclists, possibly before cars even existed. Not that that means bikes should have priority, but still, there's an emotional color there.


is about how most bicyclists behave, in all their law-eliding [sic] glory. But flexibly: basic message is that, gasp, bicyclists are situational and adaptive, and may be doing what seems best to them at the time. And I found myself guilty of the Fundamental Attribution Error: when I go the wrong way on a one-way street, it's to go a short distance to reach a destination without ridiculous detour. When I see other bikers do so, I assume they're just flagrantly breaking the law, not doing the same thing I am.

(I've also seen cars go the wrong way, again to go a short way to a driveway without going around a block... I understand but feel condemnatory anyway, because *car*.)

I was feeling moralistic about going the wrong way down a bike lane, but

A bicyclist whose destination is the wrong way up a one-way street, for example, might choose to ride against traffic if the alternative is a considerably longer route. A cyclist turning left on a busy street with four lanes may decide that it makes sense to ride the left bike lane to a destination half a block up the road on the left; otherwise, the cyclist would have to cross four lanes, ride a short distance, then cross back again, exposing himself to greater risk.

Hiles talks about the concept of 'affordances', via Don Norman but also a thing in Gibsonian psychology, and how the low speeds and narrow width and lower lethality of bicycles allows for more flexible behavior than a car, and naturally bikers exhibit more flexible behavior.

In short, compared with motorists, bicyclists have a different set of constraints and, more importantly, affordances. Norman (1988) defines “affordances” as the “perceived and actual properties of the thing, primarily those fundamental properties that determine just how the thing could possibly be used” (p. 9). Bicyclists have more diverse physical and social/legal affordances than motorists, so bicyclists exhibit a more diverse range of behaviors than motorists. If we label one style of riding “vehicular cycling,” we can dub the broader range of cyclists’ behavior as “affordance cycling,” meaning that the bicyclist’s actions are governed less by preplanned and analyzed patterns and more by what seems to make sense from among all the possible actions the bicyclist perceives in the moment. The “affordance cycling” concept may become more meaningful once we begin to explore how bike lanes influence bicyclists’ perceptions. For now, the point is that bicyclists have such varied behavior because they have so many options.

Cyclists who understand the rules of the road well know when those rules can be safely and usefully broken. Roadside researchers who make ledgers of vehicular-style behaviors versus non-vehicular-style behaviors give us data that is interesting, but that does not tell us the extent to which the supposed transgressions pose real dangers.

There's a charming vignette of 'Joe', a fat middle-aged man who bikes comically, slowly, and safely down the sidewalk, and across a crosswalk, while smoking a cigarette.

I’d wager he’s as much of an expert at pedestrian cycling as many club cyclists are at vehicular cycling. He has figured out how to get where he wants to go, and he gets there in a way that’s comfortable for him. At the speed he rides and with the care he takes, Joe may be no more at risk than a vehicular cyclist. If we judge his behavior by vehicular cycling principles, his actions are quite improper. But it’s hard to argue that Joe is a hazard to himself or anyone else on the sparsely-peopled sidewalks of downtown Fairborn, Ohio. The beauty of the bicycle is that it can accommodate both a Joe and a John Forester. And it would be just as absurd to try to make Joe into John as to try to get Forester on the sidewalk. This is not to say that Joe couldn’t practice vehicular cycling if he wanted. But what would make him want that?

Even John "Mr. Vehicular" Forester advocates treating stop signs as yield signs, and slow rolling stops to avoid having to overcome stationary friction.

And as for the scofflaw nature of it all, I was inspired to ask 'How many drivers who complain of law-breaking bicyclists, themselves violate speed limits and turn signal requirements?' I'm not sure anyone who goes 5-10 mph over the speed limit, or often doesn't use turn signals, is in a position to complain about bikers with a flexible attitude toward stop signs and sidewalks.

Of course there's adaptive, and then there is truly reckless. Zooming downhill through a low-visibility stop sign just because you don't want to brake (and nearly colliding with me[1]); biking past pedestrians at full road speed; biking at night without lights (on *or* off the sidewalk, IMO; sidewalk may protect you from cars but makes you more of a menace to pedestrians unless you're slow). And writing laws to cover complex adaptive behavior, other than "we'll ban stuff that could be risky but leave enforcement up to police judgement", is hard. OTOH, that last is more flexibility than people who issue blanket condemnations of rolling stops or sidewalking (where illegal) do.

[1] I have wondered if that biker saw me and figured the speeds were right or that he had enough control to swerve around me. I just saw someone flashing by two feet in front of me while I crossed with right of way.

See the comment count unavailable DW comments at http://mindstalk.dreamwidth.org/359415.html#comments



Damien Sullivan

Latest Month

July 2017


Powered by LiveJournal.com
Designed by Lilia Ahner