The success of Toyota's Prius sedan has helped spark both foreign and American automobile manufacturers to come up with more fuel-efficient designs. General Motors is pushing development of its new plug-in hybrid vehicle by 2010, while Ford Motor Co. plans next year to double its lineup and production of hybrids. Honda Motors announced recently it will have a new hybrid to compete at a lower price against the Prius by 2009, The Wall Street Journal reported Friday.

Rising consumer demand has meant Toyota and Ford have not been able to build enough hybrid vehicles. Contrary to many experts' assumptions, Toyota's head of North American sales, Bob Carter, has said his company makes a profit on its more than 1 million Prius hybrids sold worldwide.