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I think the slight peak in the late afternoon serious injury bar is significant. Dusk is, in my view, a particularly hazardous time. Cyclists assume they that because they can see, that they can also be seen, and that's not entirely accurate.

There's a denominator question there, too, which could be accounted for by the evening commute. A time of day x time of year analysis would shed some more twilight on the issue.

That the injury "rate" is lowest in the winter and higher in peak riding time probably just indicates that there is a greater proportion of experienced riders in winter than other times. I would hope that experienced riders are less likely to be injured on a per mile basis.

I thought about that too. And CaBi probably amplifies that. The ratio of experienced to inexperienced cyclists probably differs much more for CaBi than among general cyclists based on season. If that makes sense.

I know this is rather obvious and nothing can be done about it, but reported injuries are different than total injuries. I've known of concussions that weren't reported, for instance. Anyway, only reason I bring it up is that the kind of injuries that might be expected to happen in the winter on snow and ice might be this kind of injury. If a seasoned cyclist goes down in the snow and does his collarbone, he's not necessarily going to call an ambulance or the police.

I can't fully understand why the NPS wouldn't report injury data to NHTSA. They're both agencies of the same government. I guess there's no requirement so they don't.

Is there any way to compare this to RATES of cycling? Seems like a lot more people are cycling now, so we don't know if it's getting more or less dangerous, based on this data.

Posted too quickly. I still don't quite understand which chart shows what. Where is the CaBi data being used? What are the rates?

As for the new peak month of October, that is a bit odd. The trend historically had been that ridership begins to tail off in that month (with accident totals reflecting that). Now it kind of looks like the entire fall drop-off occurs between October and November. That could be a indicative of a permanent shift back in the fair-weather rider expiration date, which usually occurs sometime around the first extended cold and wet fall period. Better lights? Integration of riding into daily routines increasing tolerance for some coldness? Anecdotally, I have seen the seasonal drop-off shifting back 2-3 weeks in the last several years.

@Crickey: Wet leaves?

Seriously, this kind of exercise is useful for thinking about the situation, but not much as a metric. One of the things it most effectively does is show how much we don't know.

The CaBi data is not being used in any of the charts. I did that "offscreen" if you will. The rates are sort of meaningless in themselves because they are(per month):

Number of injuries in DC/
Number of CaBi riders in the region

That's useful for comparing months, but the rate is meaningless. Having said that,

October = 0.016%
February = 0.006%

@Crickey: random variation in 2014? Warming temps?

Daylight Savings Time ends in early November; the shift means that a cyclist leaving for home at 5 pm is suddenly in darkness the entire ride. That probably marks the end of fair-weather cycling each year. And the end of DST has moved back a week or so over the past few years.

Data issues: what's a "serious injury"? I've been injured badly enough to seek medical attention twice in my commuting career. I've never notified the police.

More importantly, why are the folks in Virginia crashing less than those in Maryland?

These are for crashes in DC. So more Marylanders are crashing in DC than Virginians - likely because of how much easier it is to move between MD and VA.

We crash just as much; we're just tougher and report it less. Nah, it's probably fewer VA cyclists than MD ones.

You mean easier to get from MD to DC than from VA to DC? B/c it's somewhat difficult to get from VA to MD by bike.

Yeah I meant "... MD than VA."

So, the conclusion is that DC riders are wusses? It's just a flesh wound?

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