For pedestrians and bicyclists, sharing the roads with cars can be a scary undertaking. A driver's attention may be averted from the road by talking on the phone, changing the radio station, looking at a text, talking to a passenger or any number of other distractions.
There seems to be a long-running feud between some who use four wheels to get to work and those who use two. Most of the time motorists and bicyclists are able to safely co-exist, but run-ins do happen, both of the verbal and physical variety. And in a car accident, a bicyclist runs a high risk of serious injury or even death.