Communicating Road Weather Impacts to the Traveling Public

Quantitative and anecdotal evidence has demonstrated that motorists respond to high-impact road weather forecast messages more consistently when the forecast information they receive from disparate media outlets contains the same travel impact message across all outlets. However, a multitude of forecasting and transportation entities within a given geographical area will release their own forecast for road weather information prior to a storm, placing the burden of aggregating and weighing the information on the traveling public themselves, and decreasing the effectiveness of the intended public decision support services supplied by these entities.

In an effort to better serve the end-user (the traveling public), NOAA’s National Weather Service (NWS) and the U.S. Department of Transportation (DOT) Federal Highway Administration (FHWA) have teamed up on the Pathfinder Project to build a framework that facilitates collaborative partnerships between NWS Weather Forecast Offices (WFO), State departments of transportation (DOT) and, if applicable, the DOTs’ private sector weather service provider (WSP).

A key mission shared among State DOTs and the NWS is to improve safety, mobility and the economy. Essential to accomplishing this mission is communicating information to the public to support their decision-making and preparedness when faced with rain, snow, fog, wind, flooding or other potentially impactful weather on the surface transportation system. Through collaboration on a road weather impact message, both the DOT and the NWS can better serve the needs of the public and accomplish their mission.

Here, the term impact is used to distinguish the type of forecast relayed to the public: the impact forecast adds value to a standard weather forecast by placing the weather into the context of the local transportation system. Impact considers the weather, the road surface, average traffic volumes, how the weather’s interaction with the road surface and/or vehicles will affect traffic, how effective maintenance mitigation efforts will be during the event, and so on. Time of day and traffic volume are important, as the impact of a snowstorm will be greatly increased if it is forecast to begin at 5:00 pm, just at the start of rush hour.