Saw this in the most recent Centerlines newsletter,
http://www.bikewalk.org/cl/2009/feb/0204b.html

It paints the picture of what most of us already were aware of, that
older "grid" cities are safer.

KEY TO SAFER ROADS IDENTIFIED IN CALIF. STUDY

-> According to a Jan/Feb 2009 New Urban News article, "Transportation
researchers Wesley Marshall and Norman Garrick fed the facts from more
than 130,000 vehicular crashes into their computers in recent months,
hoping for a systematic answer to a life-and-death question: How can
America's streets and roads be made safer? Highway departments have
typically focused on 'finding the most problematic locations and
fixing those roads or intersections,' say Marshall and Garrick of the
University of Connecticut's Center for Transportation and Urban
Planning. But the conventional approach doesn't go far enough, the two
researchers assert. They felt it was time for 'a more comprehensive
approach to road safety that takes into account the complete street
network.'

"Consequently the two gathered data on nine years of road safety
records for 159 California cities of 30,000 to 150,000 population, and
ultimately zeroed in on 24 medium-sized cities with some of the best
and worst crash frequencies. Their conclusion: The most unsafe cities
in California, in terms of traffic fatalities, are the newest ones --
those developed primarily since 1950. The cities with the fewest
fatalities, by contrast, are those with significant portions built
before 1950..."

Source: http://tinyurl.com/avng4g