this is interesting, from the parent: "As levels of pedestrian and bicyclist activity rise their per capita risk falls. Drivers adapt their behavior in the pres

this is interesting, from the parent: "As levels of pedestrian and bicyclist activity rise their per capita risk falls. Drivers adapt their behavior in the presence of increased cycling and walking (17)." (17) Jacobsen P. Safety in numbers: more walkers and bicyclists, safer walking and bicycling. 2003.