Turn specific vs. link based travel times calculated from floating car data

Floating car data (FCD) meanwhile is a widely available and affordable data source. The given GPS data – delivered in frequencies of some seconds or sometimes only a few minutes – are typically matched to some digital road network and mainly the traffic variables travel time or travel speed are calculated out of it, yielding current values for each link in the road network with at least one observed GPS position. With regard to route planners or navigation systems for example, the information could be even more precise as there is typically no distinction drawn between different turning directions at intersections. Taking the according and presumably varying travel times into account might result in improved navigation solutions. This contribution quantifies the travel time variations regarding different driving directions at several junctions in the German city of Berlin. For this purpose, GPS positions delivered by a fleet of about 4000 taxis covering some months of data are used. Traffic data are decomposed and the resulting turn specific travel times are compared