The primary objectives of the study were to determine the effectiveness of two types of warning letters and an informational pamphlet in reducing the subsequent collision and conviction records of pre-negligent drivers. An additional study objective was to determine the effectiveness of a follow-up reinforcement letter sent to collision and conviction free drivers. The results six months subsequent to treatment showed no significant treatment effects on convictions, but a positive pamphlet effect on collisions. The follow-up reinforcement analysis for collision and conviction free drivers showed no significant treatment effects on collisions. On convictions, however, there was a main effect attributable to type of warning letter as well as an interaction between type of warning letter, pamphlet condition, and follow-up reinforcement. No treatment conditions were significantly influenced by subject characteristics.
Abstract