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Interesting data. On reading the WashCycle post I was frustrated that the risk assessment used a distance-traveled standard, which didn't seem to be an appropriate way to compare motorized vehicles and bicycles.

On visiting the CMU site, however, I was pleased to see they also compare data using a time-of-travel standard, which I would guess is a better way to compare bikes and cars.

That data shows the relative risk of biking to be much less dangerous than using the distance-traveled standard.

Deaths per 100 million minutes traveled were 0.53 for personally owned motorized vehicles and 0.49 for bicycles. A dramatic difference from the 100 millions miles traveled standard (1.03 for personally owned motorized vehicles and 5.58 for bikes).

Still, I have no doubt that uncaged bicyclists and pedestrians are more likely to die in accidents.

The most exhaustive analysis of the risk of cycling I've ever seen is by Ken Kifer:

Of course, the underlying problem is that in calculating any cycling accident rates the denominator is going to be somewhere between a loose estimate and a wild guess, as there are no reliable statistics about bicycle use.

I guess I'm confused as to why fatalities per time is better than per mile. When I have to go some place, I never think I'll travel for x minutes and then come back. Is it that it removes highway/interstate travel (which generally is not done on a bike) from the equation?

I think Wonker's comment "I have no doubt that uncaged bicyclists and pedestrians are more likely to die in accidents" sort of sums it up for me.

I agree that stats like this make it harder to convince people to ride to work. (Of course, it should scare them from walking to work too, I guess.) But it does seem obvious (doesn't it?), that if you're not surrounded by a big medal weapon, you're more likely to get killed in an accident.

Maybe looking at fatalities on a per trip basis might yield yet another interesting yet confusing stat. The time travled makes sense to me in that it makes bike trips more comparable to car trips. That is, people have only so many minutes per day in which to travel from place to place. If you travel by car, you probably have to travel farther than someone who can travel by bike, but your time spent traveling might be about the same as the time the biker spends.

If we assume all three (pedestrian, bicycle, car) are involved in an accident, perhaps. Bikes and pedestrians should be more capable of avoiding accidents. And, while single-car collisions often result in death, single-bike and single-person collisions are much less likely to (based on empirical evidence only). But if a car hits a pedestrian or bike (or the other way around) the person in the car is safer.

Or, another way to look at it is "Cars, more than any other mode of transportation, kill people, no matter whether the victims are walking, biking or in cars."

Right, Nancy - I think that's a great way of phrasing it.

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