Paging Inspector Sands: The Costs of Informing the Public about Impending Events

We study the effects of providing the public with information about impending events. Specifically, we draw on a natural experiment to evaluate the impact that pedestrian countdown signals - timers that indicate when traffic lights will change from green to yellow - have on the behavior and safety of road users. The experiment generates exogenous differences in when a countdown signal gets installed across the intersections of a major North American city. We exploit these differences to compare the behavior and safety of road users who know exactly when traffic lights will change with that of road users who do not. We find that although countdown signals reduce the number of pedestrians struck by automobiles, they increase the number of collisions between automobiles. Using detailed data on the specific nature of collisions, we show that collisions rose because drivers who knew exactly when traffic lights would change drove more aggressively. Overall, the findings imply that welfare gains can be attained by selectively disseminating information in settings where individuals interact with others.