A long route 90 near San Antonio, brake lights are starting to flash. Twenty-five kilometers away, Sam Mendoza is sipping coffee in the region's "TransGuide" traffic management center,where 16 wall-mounted television monitors display scenes from some of the 109 video cameras peering at 100 kilometers of area highways. Suddenly, a beeping sound signals that traffic on Route 90 has slowed below 40 kilometers per hour, as sensed by some of the 1,700-odd magnetic-loop detectors embedded in the region's roads.Mendoza seizes a computer mouse and zooms a highway-mounted camera toward the problem spot; soon his monitor reveals two bearded men in the breakdown lane struggling to fix a pickup truck's flat tire.He quickly types a keyboard command, causing an arrow on an electronic sign hanging over the righthand
lane to flash from green to yellow. The light warns drivers about the flat-fixers, hopefully allowing them to avoid an accident or maybe find a different route.

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