etro networks around the world have advertisements along the walls of underground tunnels. These advertisements are still-pictures, placed contiguously so that, when they are lit up by rapidly flashing spotlights, they appear to be 15-second videos.

The technology, which is designed to present a captive train audience with 24- or 30-frame-per-second movies, depending on the speed of the train, has been created by companies like SideTrack, an outdoor advertising firm in Canada, and New York-based Submedia. ... more