Az Republic story Liability for government-issued vehicles on the rise Stated some of the obvious; bigger, sprawly cities tend to have more driving by public-sector workers, invariably leading to more liability costs to cities/taxpayers. Just another socialized cost of sprawl and automobility.
The sidebar has some interesting dollar figures for a number of Phoenix-metro area cities (and Maricopa county), all were costs paid out by the municipality over the period from ~ 2008 through 20012. A small, compact city like Tempe clocks in at $806K, Scottsdale is up at $2M. Scottsdale at a population of ~ 221K people is somewhat larger than Tempe’s 164K; but certainly not nearly triple! But Scottsdale’s land area at 186 sq.mi. is way larger than landlocked, mostly built-out Tempe’s 40 sq.miles.
Phoenix is of course the 500 pound gorilla: $23M paid out, with 1.5M people, and a whopping 517 sq. miles of land area.
Statistically speaking, Chandler seems to have a quite-low payout ratio; $203K, 240K population and 58 sq.miles — so maybe Scottsdale is just an outlier 🙂