The Federal Highway Administration (FHWA) Weather Team is coordinating weather information requirements for a range of decision makers of surface transportation modes in the context of the Intelligent Transportation System (ITS) program. The Team has produced a White Paper on the research and development issues for a conceptual Weather Information for Surface Transportation (WIST) System, and is sponsoring a multi-state regional operational test. This paper focuses on the linkage between meteorological information, decision support, and outcomes on the transportation system.
The Weather Team and the ITS program operate under the Government Performance and Results Act (GPRA). The GPRA specifies program accountability to outcomes in the transportation network environment that include: safety, travel time efficiency, mobility, user satisfaction, environmental conservation, and costs. Improved use of weather information by transportation decision makers can impact all these outcomes positively. FHWA has previously focused on Road Weather Information Systems (RWIS) that collect roadside observations and other meteorological information to improve snow removal and ice treatment in highway maintenance. This has already reduced costs and improved pavement levels of service by more intelligent dispatching of plowing and spreader trucks, while reducing environmental damage from salt applications. However, large benefits, especially in urban areas, are expected through reduction of weather-related congestion effects. This will require improved decision support, including weather information, to traffic managers, transit operators, incident responders and travelers, as well as to highway maintenance managers. This is necessary to coordinate trip planning, mode diversion, travel advisory and highway restriction decisions with snow removal and ice treatment, or with respect to other conditions that affect visibility, vehicle accelerations, vehicle stability, or lane capacity. There are still significant research challenges in finding how to optimize weather-related outcomes, including: Estimating the level of weather impacts on transportation congestion; identifying the information bottlenecks to better decision making (meteorological, pavement condition, and other transportation information); the filtering and fusion of information for probabilistic (risk) decision support, and; the human interface and dissemination of information for effective behavioral influence in adverse weather conditions. The Weather Team is formulating plans to address these issues and insert requirements into the National ITS Architecture, which is the very broad-based system design that incorporates many of the advanced technologies being implemented within the surface transportation environment.