California and the Bay Area
Motorcycle deaths in California and the Bay Area in 2007 were puzzling in a couple of ways. While deaths in the rest of the country increased by 7% from 4837 in 2006 to 5154 in 2007, in California fatalities increased by just 2% from 506 to 517 (see first attachment). The number of registered motorcycles in the state and in the US aren't available yet, but even a modest increase in the number of bikes will result in a decrease in the rate per bike in California.
But at the same time, Bay Area deaths climbed sharply in 2007, from 68 to 95--a 40% increase (see second attachment). Yet, the Bay Area rate per registered bike was well below the statewide rate in '06 and will probably stay below it in '07 as well.
I find the low rate in the Bay Area quite interesting, because urban areas tend to be higher than rural areas due to traffic hazards. With a population of several million packed into a fairly limited geographical area, you'd think the Bay Area would have higher rate. (FYI: I included the 9 counties on the Bay plus Santa Cruz.) Two possible explanations that come to mind are: 1) riding seasonality reduces exposure compared to southern counties; and 2) affluence increases the average number of motorcycles per rider. Any other ideas?
To better understand the sharp rise in deaths in the Bay Area from 2006 to 2007, I looked into two questions: How did the age distribution change, and how did the distribution by motorcycle styles change? IOW, who accounted for the increase and what kinds of bikes were they riding?
All age groups under 50 grew, with the biggest increase in the under-30 group, while the 50-and-over group decreased (see third attachment).
Sportbikes accounted for virtually all of the increase in Bay Area deaths, nearly doubling from 2006, while cruisers showed only a slight increase (see fourth attachment).
Got some thoughts about the Bay Area fatality increase? Post up your ideas and I'll try to dig up the stats.