TRAFFIC SPEED MODELLING TO IMPROVE TRAVEL TIME ESTIMATION IN OPENROUTESERVICE - Ludwig, C.; Psotta, J.; Buch, A.; Kolaxidis, N.; Fendrich, S.; Zia, M.; Fürle, J.; Rousell, A.; Zipf, A. (Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., 2023)