The paper reports on a study comparing alternative presentations of freeway speed data on maps. The goal of the study was to inform the design of displays of real time speed data over the Internet to the general public. Subjects were presented with a series of displays and asked to rate their preferences. We looked at different choices of color (3 colors, 6 colors or a continuous range), and proposed line, sensor, and segment representations of the speed data. We also collected feedback on more complex displays such as comparison between current and "normal" speeds, and a chart of speed variation over a period of time at given locations. (Also cross-referenced as HCIL-TR-2000-23) (Also cross-referenced as UMIACS-TR-2000-73)