The Evaluation of Traffic Control in Changsha City

Different aspects of the traffic control system in the CBD of Changsha have been evaluated. A general issue is the safety conditions, which are evaluated qualitatively. The second issue is the low saturation flow observed on the intersections, that appear to be 20 to 30% lower than the ones in comparable situations in Europe or North America. Travel times could be determined rather well using GPS data from taxis. That method was validated using video observations. Bluetooth scanners have been tested for the measurement of travel time, but they appear less suited in urban areas. The paper evaluates the accuracy and reliability of the loop detectors in the traffic control system SCATS. Lastly, the signal timing of a 13- nodes network in the CBD of Changsha has been optimized with TRANSYT-14. This optimized (fixed time) control showed a significant better performance than the control by the SCATS system.