A study of the usability of statewide web-based traveler information systems was conducted to assess their effectiveness in conveying road and weather information to travelers. Guidelines from traveler information systems and the website design literature were coalesced to create an assessment framework to include important elements from a user's perspective. Ninety-eight travelers from the State College, Pennsylvania, area visited web-based roadway weather information systems for Pennsylvania, Maryland, and Ohio as part of a laboratory-based trip-planning experiment and provided ratings of site attributes. Site ratings revealed that it was important that travelers accessed information about conditions along their intended route with minimal searching. Map scale and resolution were important graphical elements. The most relevant weather information elements identified by users were precipitation type, road surface condition, visibility, and air temperature.