The Centers for Disease Control and Prevention has compiled a lot of data on the relative dangers associated with walking or running as compared to driving:
In 2012, 4,743 pedestrians were killed in traffic crashes in the United States, and another 76,000 pedestrians were injured.1 This averages to one crash-related pedestrian death every 2 hours, and a pedestrian injury every 7 minutes. Pedestrians are 1.5 times more likely than passenger vehicle occupants to be killed in a car crash on each trip.
There are certain factors that highly correlate with pedestrian accidents. Older people and young children are much more likely to be involved in accidents as pedestrians.