Fig. 1From: Travel time predictions: should one model speeds or travel times?Location of the test sites. a Hietzing, b Westbahnhof, c Ring, d Südosttangente. The colour of the arrows indicates for a given link the percentage of time intervals for which at least one observation is obtained (white=0%, orange = 50%, black = 100%). Background image: ⒸGoogle mapsBack to article page