Programs that target drivers with poor records can reduce future traffic violations and crashes, according to a new study sponsored by the Institute. However, not all such programs work. Court-initiated education for violators failed to reduce future crash risk.
Based on these findings, the researchers questioned "the appropriateness of the growing use of court traffic violator schools and home study programs (such as internet courses) for which the triggering violation is dismissed upon completion" of the education. The result is a reduced chance that future violations will lead to measures that effectively reduce violations and crashes.
The researchers examined 106 approaches from traffic school to license suspension as well as simpler forms of intervention including warning letters aimed at violators. The study specifically excluded interventions that are triggered by alcohol-related violations.
As a group, these measures can produce small but significant reductions in future violations and crashes, the study found. One year after intervention, researchers found an average 6 percent reduction in crashes and 8 percent reduction in violations. These effects are greater than had been reported in a previous review sponsored by the Institute (see "Training may reduce tickets without affecting collisions," July 29, 1989). But the researchers also found wide variations in the effectiveness of the approaches. Some work better than others, and some apparently don't work at all.
License suspension or revocation showed the largest reductions in subsequent crashes (17 percent reduction) and violations (21 percent). The distribution of educational or informational materials had no effect on either crashes or violations. Court-initiated education for violators reduced future offenses but didn't reduce future crash risks. These findings are consistent with Institute research findings that date back to 1984 (see "Defensive driving courses fail to trim crash rates," May 12, 1984).
Warning letters also reduced crashes (4 percent reduction) and violations (6 percent). Although this approach had the smallest measurable effect on crashes, the letters reached the largest number of drivers at the lowest cost per driver.