The second gasoline/electric hybrid car on the U.S. market (after Honda's Insight) was redesigned for 2004, growing in size, power and features, but not base price. Toyota morphed Prius from a 4-dr sedan to a sloped-roof 4-dr hatchback that added 6.9 inches in wheelbase, 6.3 in overall length, 1.2 inches in height and nearly 2 inches in width. Curb weight rose by some 125 lb. Though still classed as a compact, this larger new Prius rivaled Toyota's midsize Camry sedan for passenger and cargo room, yet boasted some of the industry's highest EPA fuel-economy ratings with estimates of no less than 60 mpg city, 55 highway. As in the 2001-03 Prius, a 1.5-liter 4-cyl gasoline engine paired with a battery-driven electric motor to drive the front wheels through a continuously variable automatic transmission, or CVT. Depending on driving needs, the car used one or both power sources as directed by a powertrain computer, though it always moved off on electric power, with the gas engine cutting in around 20 mph or so. The system allowed the motor to act as generator for charging the battery pack, so no plugging-in was required. Like other CVTs, the Prius transmission dispensed with fixed gears to furnish a near-infinite number of drive ratios, again determined by the powertrain computer. New "by-wire" electronics replaced mechanical linkages for the accelerator and shift lever. Also aiding efficiency were a power-steering pump and air-conditioning compressor driven by electric motors instead of power-sapping engine-driven belts. Another new powertrain feature was a "hill acceleration control" designed to maintain a steady speed up and down steep slopes. The result of all this was a combined 133 peak horsepower. Antilock brakes remained standard, joined by traction control and a newly optional antiskid system. Front side airbags and front/rear curtain side airbags were also available for the first time. Other new options included xenon headlamps and a "smart" keyless entry/engine-starting system with pocket transmitter. The optional navigation system added voice-command capability. As before, it operated from a central dashboard touch-screen that also governed various audio and climate controls. Continued were real-time screen displays for "power flow" and instant and average fuel economy. For all the changes, Toyota held the Prius price line for 2004, claiming it could do so because it was finally making money on its hybrid car. (Many suspected Toyota had subsidized earlier models.) That plus the fresh design produced strong buyer demand, helped by Prius-owning Hollywood notables and other grandees who gave this hybrid high social status. Not surprisingly, Prius was soon in short supply, with long waiting lists and hefty dealer markups the rule. The situation continued into 2005, spurred by a midyear spike in gas prices and despite more cars being available for the U.S. market. Though several larger gas/electric cars were available by 2006-including a first-ever hybrid Camry sedan-Prius remained a hot seller as gas prices hit a record $3-plus, with $4 a gallon seemingly inevitable and imminent. As before, Prius' only competition as a compact hybrid car came from Honda: the two-seat Insight coupe and the larger, more-conventional Civic Hybrid sedan. Insight was dropped after 2006 due to waning sales, but the Civic loomed a stronger challenger that season, thanks to a redesign of its own. Yet for all the hype and hullabaloo, hybrid vehicles still account for only a small percentage of new-vehicle sales, and few have reached the secondhand market at this point. Hybrids do seem here to stay, but their ultimate impact is anything but clear.