Age differences in response to high and low-threat driver improvement warning letters

Abstract This paper is based on an evaluation of Oregon's Driver Improvement Program, which monitors driver records and takes corrective administrative action at four levels. This paper focuses on the second step in the program, the warning letter. Data are based on drivers who qualified for warning letters in 1993. Records of 8,462 letter recipients and 456 controls were monitored for 26–38 subsequent months. Of 8,462 letter recipients, 4,184 received a standard letter and 4,278 an experimental soft-sell letter. Overall, the effect of letters on accidents and moving violations depends on age. The program seems to work as intended for people over 25. Both letters are effective, and the soft-sell letter is the more effective of the two. However, for people under 25, accident free survival is significantly poorer for both letter groups, and differences in effectiveness between the letters are smaller.