A human factors study consisting of a vehicle headway analysis and a questionnaire survey was conducted in Rhode Island (RI) to investigate tailgating issues and possible means for tailgating treatment. Vehicle headways were collected from highway surveillance videos and serious tailgating issues were identified on RI highways. The results of the questionnaire survey further confirmed the observations made in the vehicle headway analysis that most RI drivers maintained insufficient vehicle headways on highways. Among a few tailgating treatments presented in the survey, most subjects preferred a system consisting of equally spaced, white horizontal bars marked on pavement and overhead graphic-aided dynamic message signs.
