Do traffic safety interventions work? The Munk School’s Jonathan Hall co-authored a study in Texas showing that the number of crashes actually increases by a few percentage points when motorists are confronted with displays indicating the number of road fatalities in the area (see the Perspective by Ullman and Chrysler). The authors suggest that this counterintuitive finding results from a cognitive overload experienced by drivers when confronted with multiple notices and instructions on complex stretches of road, leading to distraction. They conclude that traffic safety “nudges” need to be carefully designed and positioned to avoid backfiring.

Read the study.