Red or Green: Estimating the Patterns of Traffic Signals Through Cyclists´ GPS Tracks for Real-Time Navigation

Advanced routing and navigation incorporating real time traffic information is state of the art - at least for car drivers. The potential of cyclists using digital navigation even to reach familiar destinations is rising but adequate technology is not available yet. For realistic routing and real-time cycling assistance, profound knowledge about expected waiting times at traffic signals and cycling behavior between the stops is essential. GPS tracks of cyclists can be used to obtain both. This paper presents a first step in this direction by suggesting methods to analyze waiting times at signaled junctions. Furthermore, user profiles representing cycling behavior in urban areas is extracted from cycling trajectories. An algorithm to identify signal control cycle times for intersections is proposed. Waiting times and speed gradients are analyzed to estimate the offset times and green-light duration. GPS tracks have been acquired by cyclists riding specific routes between two locations in the city center of Vienna. Methods to preprocess the GPS tracks are applied. From these cleaned tracks cyclists´ profiles are calculated to show the behavior in free flow traffic between traffic lights. This paper finally shows results of both estimating the signal cycle time and the single pattern at a bidirectional route with ten traffic lights. Positive verification is conducted comparing the GPS track based result to the real signal programs.