Here’s yet another way of looking at the health benefits of reducing sprawl: denser cities with more transit ridership tend to have fewer traffic deaths. Take a look:
Fatalities (on the vertical axis) include deaths among pedestrians, transit riders, and automobile drivers and passengers.
The upshot is that U.S. cities with high levels of transit ridership—especially those with large rail systems—also tend to have low traffic fatalities. But cities that are more sprawling (and which tend to have bus-only transit systems) tend to have higher rates of traffic deaths.
(This graph was taken from Todd Litman’s paper, "Comprehensive Evaluation of Rail Transit Benefits" available on the Victoria Transport Policy Institue website.)