The Lexus GS 450h is not a tree-hugger hybrid. The electric motor in this luxury sedan is meant to maximize performance, not fuel efficiency. By Mark Solheim, Editor March 17, 2006 Traffic is crawling across Hoover Dam, and my foot is getting tired of pressing the brake pedal instead of the accelerator. Tourists crowd the top of the dam, photographing the massive structure that created the 247-square-mile Lake Meade. On the other side of the lake, the dam wall sweeps down dramatically to the Colorado River, which snakes into the distance toward the Grand Canyon. I'm in the desert just 40 miles outside of Las Vegas driving the Lexus GS 450h, the world's first luxury performance hybrid sedan, and inside the car it's eerily quiet. At slow stop-and-go speeds, the gas engine remains dormant and the car is propelled by a large and nearly silent electric motor. When the traffic finally thins, I step on the gas and the car snaps into action, accelerating effortlessly and without a hint of hesitation. Not a tree-hugger hybrid The GS 450h comes from the same company that produces the Prius. Both cars combine a gasoline engine with electric motor power, but, after that, any comparisons end. Whereas the philosophy behind the Prius is to use the electric motor to maximize fuel efficiency, the purpose of the 450h's electric power is to maximize performance. Consider that the 450h accelerates from zero to 60 mph in 5.2 seconds -- about the same as the Porsche 911. Top speed is electronically limited to 131 miles per hour, and judging by how quickly I reached 110 mph on a desert straightaway, it could do more. The secret is that the electric motor that helps drive the rear wheels instantly delivers power. And the car has electronically controlled variable transmission, so you don't have to shift through five or six gears. The V6 engine combined with the electric motors produce 339 horsepower. Even with its performance orientation, the 450h has some environmentally friendly bragging rights. Fuel economy is a so-so (by hybrid standards) 25 mpg city and 28 highway -- but it's still a lot better than the 18/25 mpg of its V8 gas-engine sister, the GS 430. And it emits 80% fewer smog-causing emissions than its V8 competitors, according to the company. Nice at a price Lexus GS 450h The car will be at dealers in May, but you'll probably have to get in line to buy one. Production will be limited, at least at first, to only 2,000 a year, and dealers already have started waiting lists. Sticker price is $54,900 -- about $4,000 more than the GS 430. Safety is state of the art, with a "vehicle dynamics integrated management" system, which is designed to anticipate a skid or slide and then correct the problem with a combination of braking, throttle and steering control. You also get eight air bags. The hybrid also has the same spiffy interior as the conventional GS line. It also has the same shortcomings -- in particular its limited visibility out the back, due to the elevated rear end. Lexus has anticipated the problem and offers an optional navigation system with a rear backup camera.