Toyota Motor Corp. is poised to introduce its 2010 Prius, the world's top-selling hybrid, to a shrinking U.S. auto market that now includes a cheaper, revamped competitor from Honda Motor Co.

With a pledge to "build to demand," the goal of selling 180,000 units in the car's first year starting in mid-2009 may have to be dialed back, Bob Carter, vice president for U.S. sales, told a recent briefing in Yountville, Calif.

Fuel at less than half of last year's peak and the weakest industry sales since the early 1980s are casting doubt on Toyota's plan to revive the model after 2008 deliveries fell 12 percent. Even with improved mileage, the Prius also may lose buyers in the recession to Honda's gasoline-electric Insight.