Fig. 2
From: Travel time predictions: should one model speeds or travel times?
Empirical cumulative distribution functions (ECDF) for data availability for a links, b days, c time-of-day-intervals given as relative frequency of observations. d provides ECDFs for the number of taxi observations per link per day per interval. Hietzing (blue), Westbahnhof (black, dotted), Ring (red, dashed), Südosttangente (green, dash-dotted)