« Monday Morning Commute - Group | Main | Monday Afternoon Commute - Survey Says »

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

Sounds like CaBi is the safest way to get anywhere in DC. Maybe the guy with the baby on the CaBi bike had the right idea.

1.32 crashes out of a total of 436 crashes is 0.27% not 0.003%.

To your caveat #2, that observed proportion of CaBi/all cyclists is consistent with total CaBi trips as a proportion of all bicycle trips estimated by the WDC region household travel survey (around 10-11%).

so the statistics show that the lack of helmets makes cycling safer?

(yes, I know that's not how it works, but when did logic enter the helmet discussion?)

Numbers are not so much my thing, but is the crash per trip metric preferable to crashes per mile traveled for any particular reason? Also, I wonder if you could extrapolate from the National Bike Challenge numbers to help fill in some gaps. I mean, you have cyclists logging every trip they do and exactly how many miles each trip is, every day of the week...that data has to be worth something, right?

I'm not sure I understand this part
"ridership was about 1/4 what it is now and only for 1/4 of the year"
Are you trying to estimate yearly crashes based on partial 2010 data?
Then 1.32 *4 (for full year) *4 (for current ridership) is 21.1 crashes per year or 4.8% of the 2010 reported total.

FWIW, Metro PD rarely cites the type of vehicle in accidents unless they cause injury. So the # of accidents is probably twice the figure.

FWIW, Metro PD rarely cites the type of vehicle in accidents unless they cause injury.

One could argue that a crash on a bike that doesn't "cause injury" isn't actually a crash.

There is no such animal as "2.31 times less."

"One time less" would equal zero.

You know what I mean...

is the crash per trip metric preferable to crashes per mile traveled for any particular reason?

Only because we have data for it. Otherwise, no. I'd rather have the crash rate per mile, which is what I was going for in Caveat #3.

I take that back. It shouldn't matter. The real metric is per unit of time (exposure). And since the measure we have is the ratio of cyclists at any given time, we have the ratio of CaBi users to personal bike users per unit of time. So, ignore caveat #3.

RayN, that's what I was going for. I'll update the post. This is what happens when you blog at 1:15 in the morning because you got home late after seeing Prometheus and spending at least 30 minutes trying to figure out what the hell was going on with that movie.

T, that may be true, but it would be equally true for both CaBi and for personal bikes.

I support Washcycle movie reviews...how was Prometheus?

It was entertaining. At times it was brilliant. At other times it was just really stupid - and for no reason. The problems with plot were so easy to fix

But mostly it was a mess. It was, like Donnie Darko or 2001, a movie that fails to give you all the pieces you need to understand it. You need to go elsewhere to get those pieces. So that's frustrating. I kind of judge movies on their script more than anything else and this one showed all the strengths and weaknesses of any Damon Lindelof project. There were a lot of scenes, facts and characters that don't really add anything to the story - so why are they there? I look forward to watching the director's cut when hopefully it can be fixed.

Perhaps the metrics are even further skewed by the fact that you might want to report accidents on the CaBi so that you don't get hit with other charges from CaBi, while an accident on your own bike you might just brush off.

I expect there is much greater CaBi use on pavement and trails, versus roads. Thus, a lower accident rate on CaBi would be a proxy for safety riding on separated facilities versus roads shared with cars.

I expect there is much greater CaBi use on pavement and trails, versus roads.

I don't see any evidence for this at all. (Not saying you're wrong, just saying I don't see it.)

Oboe: I completely agree. Its all conjecture. Even with the evidence we have, there are so many factors between the groups that I seriously doubt we could ever tease out the relative contribution. That said, I am glad to Wash's analysis: any analysis goes into the database for further cruching with the next study.

The comments to this entry are closed.

Banner design by creativecouchdesigns.com

City Paper's Best Local Bike Blog 2009

Categories

 Subscribe in a reader