Does Getting Forecasts Earlier Matter? Evidence from Winter Advisories and Vehicle Crashes

Significant investments are directed toward improving the accuracy and early availability of forecasts. However, the value of longer lead times on forecasts is unclear. Using data on winter weather advisories and vehicle crashes in the US, I show that advisories with longer lead times reduce crashes, even when they are less accurate than advisories with shorter lead times. Further, marginal benefits do not decrease with lead time. The benefits come from individual and institutional responses. When advisories arrive earlier, people visit fewer places, and snowplow crews intensify the road maintenance operations. These results have policy implications for providing effective forecasts.