This paper describes a study of travel speed of vehicles passing community which located on roadside of rural highways. The objectives of this paper were to survey the number of vehicles which drove with excessive speed over speed limit of both outside and inside community area. To survey the operating speed and to survey operating speed after traffic engineering measures installation on study area. Ban Pa Yang community, Muang district in Nakhon Si Thammarat (NST) was selected as a study area. Traffic engineering measures will be selected from the speed survey results of vehicles passing community. The study results showed that the top three volumes of vehicles passing community were motorcycles, private cars and pick-up trucks, respectively. The survey results of operating speed showed that private cars drove passing community with excessive speed over speed limit of highways, however, the operating speed of trucks were gradually reduced before entering community and increased over speed limit again when passing community zone. Motorcycles were the only one vehicle type which drove lower than speed limits of both outside and inside community zone. Transition zone area was a traffic engineering measure which was defined the distance for reducing speed before entering community by calculated from the data of speed survey outside community area. The average operating speed outside and inside community study area was evaluated by paired-sample t – test statistic. The survey results showed that the average operating speed of trucks and motorcycles after measures installation on transition zone were lower than the average operating speed of trucks and motorcycles before measures installation significant at a confidence level of 95%.
Keywords : Operating speed, Speed at 85th percentiles, Transition zone area