This research collects traffic data, particularly the times for each vehicle that can make a U-turn without any interference from traffic in the opposite direction, at urban U-turn locations to analyze the U-turn’s saturation flows. The data are then used to find whether geometric designs can influence the saturation flows and determine the passenger car equivalent values of different vehicle types at the U-turn locations. The study includes twenty U-Turn locations with four distinct physical characteristics, i.e., 1) U-Turns at signalized intersection, 2) grade-separated U-Turns, 3) Mid-block U-Turns with police control, and 4) Mid-block U-Turns without police control. At each location, vehicle types as well as their U-Turn departure times from reference line are collected along with site’s physical geometric design. The findings from this research show that U-turn lane widths significantly affect U-turn’s saturation flows only for a midblock U-turn type but not for others. Therefore, traffic designers would focus on this factor for better U-turn operations. Additionally, the passenger-car-equivalent numbers of different vehicle types and the effect of car-following during U-turn operations were calculated and could be used for further references in traffic engineering design and analysis.
