Statistically, how beneficial are truck and trailer graphics?

Studies by the American Trucking Association and RY&P Advertising found that: 98% of consumers feel fleet graphics created a positive image for the company 96% said fleet graphics had more impact than billboards 91% of all people notice the words and pictures displayed on trucks 75% of consumers develop an impression about a company and its products based on its vehicle graphics 29% of consumers said they would base a buying decision on the impression they received of a company displaying vehicle graphics

How cost effective are trailer graphics compared to other advertising options. *Note: Study taken from 3M promotional flyer.