The Letjend S. Parman Purbalingga road section is the main road along which there are many shops, schools and government offices, the cause of the decrease in vehicle speed is side barriers and U-Turns. The purpose of this study was to determine the volume of traffic and side barriers, road performance, and the effect of side barriers and U-Turn on vehicle speed. The data used is primary data, namely data on traffic volume, side barriers, U-Turn vehicles and vehicle speeds and secondary data, namely the population of Purbalingga 2021. The location of this research was carried out on the Letjend S. Parman Purbalingga road along 200 meters. The method used is the MKJI method, 1997. The results of data processing show that the maximum traffic volume occurs on Mondays at 841.95 pcu/hour in the north-south direction and on Sundays at 616.0 pcu/hour in the north-south direction. , the highest side resistance occurred on Monday at 350.9 sf/hour in the north-south direction. The degree of saturation is 0.47 for Sunday and 0.53 for Monday so that the service level is C. The percentage decrease in speed for the north-south direction is 45.5% for Sunday and 41.1% for Monday, for the south-east direction. north by 54.2% for Sunday and 34.1% for Monday. Side barriers and U-Turn are factors that cause a decrease in vehicle speed