Using GTFS data, STLTransit has created videos showing all of the transit vehicles in a city over one day. Here’s Washington’s.

Via PlanItMetro.

The video shows one dot for each schduled Metrorail, Metrobus and Circulator vehicle. View the video in full screen (click the rectangular icon in the lower right of the video) to more clearly see the trains, which the video shows in a color corresponding to their line.