November 10, 2013
is a comment containing this link
to a study by Kenneth D. Cross and Gary Fisher which is cited by John Forester in Effective Cycling to support his claim that accidents where the cyclist is hit from behind are not a large risk, and thus we should not be afraid to ride with traffic and even somewhat in the part of the road where automobiles commonly travel. I believed this claim for decades, because presumably he would represent that study fairly, and not cherry pick or distort the data to support his position.
What can I say, I was young and naive, right?
Surprising to me, when you read the cited statistics, you discover that things are not exactly the way Forester claimed. Accidents in which cyclists are hit from the rear (Problem Type 13, p. 33) cause 23.4% of the fatalities. That’s not at all the impression you would get from reading Forester. It is true that 70% of these fatalities occur on narrow, rural roads at night, and alchohol is often involved, but that still leaves 7% of all fatalities in the non-narrow+rural+night case of hit from behind.
Is 7% large? Probably. Riding against traffic poses a significant risk of injury (p. 174, a factor in 20.1% of injuries) but only a 4.8% risk of a fatal injury.
In contrast, sidewalk riding in the presence of driveways (Problem Type 8, p. 31) is not nearly as dangerous as portrayed by Forester — no fatalities! (Yes, there are injuries, 5.3% of the total).
And thus my opinion of Effective Cycling takes another lurch downwards. The study itself is interesting; what I read there makes me feel happy about my decision to equip my bike (and all my kids’ bikes) with hub-powered lights that are always on when the bike is rolling; again and again, visibility is a factor.
November 10, 2013
In a comment exchange on some random liberal blog, a transit advocate was mysteriously opposed to bicycles-as-transit. He never completely explained why, but I think he was making assumptions about road damage and congestion that assumed a linear relationship to weight. However, that’s just not so. Damage-per-wheel is at least proportional to the cube of the weight on the wheel, if not the fourth power. It’s very non-linear, and non-intuitively a heavy vehicle with many wheels can do less road damage than a lighter vehicle with just a few.
Turns out, a city bus can do a LOT of damage, and per-passenger, it does over twice the damage of even a single-occupancy SUV. A plan-loaded city bus is almost as bad for roads as a fully loaded semi truck, and a crush-loaded city bus is worse. Whether you calculate it as marginal damage per passenger, or average damage per passenger, a bus passenger is hundreds of times more damaging to the road than even a fully-loaded cargo bike, and thousands of times more damaging than someone merely carrying themselves on a bicycle. Even the marginal road-damage cost of the first passenger to board a bus is a little bit worse than the road-damage cost of a single-occupancy SUV.
I’m not at all sure that these costs are rolled into the published “costs” of transit. Note that these are not the only costs; there are congestion costs, parking space costs, fuel costs, risk-to-others costs, risks-to-rides costs. But the road damage costs are really large.
(And if someone knows more about this than I do, do please check my math, I am working from published sources and conservative estimates. This was surprising to me.) Read the rest of this entry »
November 10, 2013
Standard US anti-cycling claim: “We’re too spread out, not like those dense European countries.”
Here’s the copy-and-paste from Calca:
density(area, population) = population/area http://en.wikipedia.org/wiki/New_York_metropolitan_area NYCMetro_area = 13,318 NYCMetro_population = 23,508,600 density(NYCMetro_area, NYCMetro_population) => 1,765.175 http://en.wikipedia.org/wiki/Netherlands Netherlands_area = 16,039 Netherlands_population = 16,819,595 density(Netherlands_area, Netherlands_population) => 1,048.6686 http://en.wikipedia.org/wiki/Massachusetts Massachusetts_area = 10,555 Massachusetts_population = 6,646,144 density(Massachusetts_area, Massachusetts_population) => 629.6678 http://en.wikipedia.org/wiki/Denmark Denmark_area = 16,562.1 Denmark_population = 5,602,536 density(Denmark_area, Denmark_population) => 338.2745
And if you notice, there’s a whole lot of Western Massachusetts that’s relatively empty (and also relatively hilly), but that works against the “we’re spread out” claim; if the west is sparse, then the east must be even denser.
And no, we do not have a uniform transit policy across the nation — how many subways are there in Montana or Alaska? We do what’s locally appropriate.
October 20, 2013
Hippie, or hypocrite, either way, you can’t be a credible advocate.
Say you’re an advocate for doing something about climate change. If you’re Al Gore, clearly you’re not credible, because you own a big house. If you’re Eric Holthaus, decide that you’ll stop flying, are a vegetarian, and consider getting a vasectomy, you’re clearly some sort of a weirdo, and who would listen to a weirdo?
June 18, 2013
Among our excuses for not riding bicycles is that America is too spread out. This explains why we don’t ride cross country very often, but not why we don’t ride to the grocery store. In fact, a whole lot of us live in places that are quite dense. I attempted to graph this before using 2000 Census data and “50K areas” but I was unhappy with the result, both because of my errors and because 50K area leaves out a lot (I live in a town of 25000, for example).
Happily, with new data, organized by non-overlapping zipcode, I can solve both those problems. One sixth of us (52 million people) live in places denser than 5362 per square mile; the next sixth, denser than 2786 per square mile, the next sixth, denser than 1292 per square mile (that’s the median density for our population; half of us live in zipcodes less dense than that, too). With all the zipcodes included it’s clear that many of us live in plenty-dense places.
I’ve tagged the graph with densities of towns and cities near Boston, mostly inside 128, plus all of Boston, and also plus three European cities known for their relatively high bike trip share. I added some other US cities for comparison. Read the rest of this entry »
We went for a ride on the tandem today (actually, months ago, I sat on this for a while), into Cambridge, to Inman Square, and we had to get there reasonably quickly. The conclusion from the stoker S was “that was not much fun; I would do it again on the tandem, but not on my own”. For all the claimed bike-friendliness of Cambridge, they’ve got a long long way to go.
The two main problems are (1) that the calm routes are not direct, and the direct routes are not calm and (2) avoiding nasty traffic and tight spots requires improvisation that is technically illegal, which makes it unsettling to many people, and hides it from official discussion of routes and infrastructure planning.
And people need to understand — me, personally, it’s good enough, but I’m a member of the biking 1% who tolerates traffic. The rest of you people, if you think to yourself, “gee, I’d like to commute to work on my bike, I need to lose 20 pounds, and I HATE parking in Cambridge” — until Cambridge gets serious, it’s probably not going to happen for you. You’ll try it, and hate it. And it’s not your fault; it’s Cambridge’s fault. Read the rest of this entry »
March 23, 2013
Dear Burlington Planners,
I don’t live in Burlington, but I work in Burlington, and I often ride my bike to work, and what keeps me from riding to work more often is the abominable cycling and pedestrian facilities that you (Burlington) provide. I think you can and should do better. In addition, a friend of ours has a somewhat-special-needs son who works at the Dollar Tree; he cannot drive, but with a few road improvements in Burlington he could probably ride a bicycle to work, which would be better for everyone involved. Read the rest of this entry »
January 21, 2013
What is the matter with Mary Jane?
She’s crying with all her might and main,
And she won’t use the bike lane – ice pudding again -
What is the matter with Mary Jane?
Pictures taken January 8, snow from before the New Year.
But at least, when we get to the light, bicycles have their very own plowed lane:
December 13, 2012
Also known as “math”.
Apparently some conservatives and other deluded souls believe that our appallingly low life expectancy is not a healthcare result, but is instead caused by excess (misclassified, not health-related) infant mortality and excess violence. This, like many conservative beliefs, is bullshit. Proof:
Suppose we have a “true” life expectancy, but two subpopulations that die early for non-medical reasons and drag it down. The “misclassified infant death” subpopulation dies at age 0, and accounts for about 0.003 of our deaths (that is, the excess US infant mortality rate is about 3 per 1000). The “murder death” subpopulation dies at an average age of 25 (a guess), and accounts for 15,000 deaths per year out of a total of 2,500,000 or 0.006 of our deaths. The reported US life expectancy is 78.37 years, and this is equal to the adjusted life expectancy * 0.991 + 25 * 0.006 + 0 * 0.003.
That is, adjusted = (78.37 – 25 * 0.006) / 0.991 = 78.93.
Without adjusting ANY OTHER COUNTRIES (Portugal’s infant mortality rate is better than ours, but not first-class) for worse-than-hoped infant mortality or murders, we move all the way from #49 to #44. That’s not much to brag about.
Update, the claim is it’s traffic accidents
Because I am feeling lazy and generous, I’ll assume average age 30, erase ALL of them, the death rate is 33,808/2,500,000 = 0.0135.
adjusted = (78.37 – 25 * 0.006 – 30 * 0.0135) / 0.9775 = 79.6.
That’s #37 in the list. USA! USA! USA!
That figure is overly generous and should not be relied on, because there are other countries between #49 and #37 with relatively high traffic death rates that would also be “corrected” upwards in the same way, among them Belgium and South Korea.
Further update — what if we try to factor in the exercise that we don’t get because we drive cars to excess?
That might matter. The years-of-life penalty is estimated to be 2-5 years, though it can be made up with other forms of exercise. +2 years takes us out of the embarrassing weeds, and up into the top ranks. However, again, one-must-apply-the-correction-equally; even in the Netherlands, even in Denmark, many people do drive automobiles to excess (how do you think they were able to do these studies in the first place?)
October 29, 2012
I read, over on comments on a blog entry at the Atlantic, that New York City government employees are asked to report to work tomorrow, even though the subways are likely to be out of order, and at least one of those employees is peeved at the prospect of traveling seven miles by foot.
And I know if I say “you could ride a bike — in fact I plan to ride a bike to work tomorrow, 10 miles, because of the likely traffic jams”, that this mere statement of fact will mark me as a smug asshole, totally out of touch with the life of ordinary-salt-of-the-earth-Americans. But in fact, if you rode a bike often enough to stay in some semblance of shape, you could do this, and your mayor is even putting in all sorts of bike lanes and cycle tracks to make this somewhat easier, and would probably have installed even more by now if ordinary-salt-of-the-earth-Americans did not make such a tremendous fuss every time he installed a new one.