According to a 2008 survey, an estimated 8.4 percent of all US drivers experienced a police traffic stop. 152 Overall, the vast majority of drivers stopped (84.5%) believed that the police did so for a legitimate reason.

However, perceptions varied based on the reason for the stop. For example, while 90 percent of drivers stopped for speeding felt that the stop was for a legitimate reason, only about three-quarters of drivers stopped for a stop sign or red light violations, illegal turn, or roadside sobriety checkpoint thought that the stop was legitimate.

Why do you suppose perceptions varied? Why was the authority of the police called into question for some stops and not others?