U.S. sales of hybrid vehicles - powered by a combination of gasoline engine and electric motor - are on a steep climb these days. The hybrid is making the transition from a curiosity to the motoring mainstream.
Japan's biggest automaker, Toyota, unveiled the world's first hybrid, called the Prius, in 1997. The history of the hybrid in America began with the introduction of the Honda Insight, a small two-seat coupe in late 1999.
The hybrid's reasons for being are: greater fuel economy and lower exhaust emissions. And it boasts an important advantage over the pure electric car - it never needs to be plugged in to re-charge the batteries.
According to R.L. Polk & Company, a firm that collects and interprets automotive information, the number of Americans driving hybrid cars jumped more than 25 percent in the past year. Mark Pauze, a Polk analyst, says the strong growth should continue.
"Right now, there are the two major players, which are the Honda Civic and the Toyota Prius," he said. "But in the coming year, there will be several pickups [trucks], an SUV [sport utility vehicle] and a midsize vehicle as well that will be offered with a hybrid engine and that will get it more into the mainstream."
Mark Pauze has a second reason in mind that should promote continued growth.
"The other thing, I guess, to be looking at is the price of gasoline," he said. "And that may move some folks to think about it more seriously beyond just a curiosity."
Honda's commitment to pushing hybrids into the mainstream is clear from the comments of company spokesman Chris Naughton.
"We've announced just recently that we'll be introducing the [midsize sedan] Accord V-6 Hybrid later this year," he said. "Whereas the Civic Hybrid was mainly designed for very good fuel economy - and primarily fuel economy - the Accord VD-6 Hybrid will be better fuel economy, similar to a Civic sedan, but also better performance than the existing V-6 sedan, so very good performance."
Sales of hybrids are concentrated on the east and west coasts of the U.S. at the moment. California, long the nation's biggest market for cars, leads the pack, says Polk's Mark Pauze.
"Low emissions and better [fuel] mileage has always been a high priority for that whole state," he said. "But California, Virginia and Florida, Maryland and Washington state - they're the top five states right now for hybrid registrations."
Hybrid buyers are paying a premium over the cost of a comparable conventionally-powered car of between $2,000 and $3,000. We asked Honda's Chris Naughton why more money?
"You've got a four-cylinder gasoline engine in the Civic Hybrid and, in addition to that, you've got an electric motor and then the accompanying parts that make the hybrid work which are the battery and the control unit," he replied.
In 2003, there were over 43,000 hybrid cars registered in the United States, but matched against total U.S. sales of more than 16 million, that's still a tiny fraction of the vehicle population. But with both Ford and General Motors unveiling hybrid SUVs and pickup trucks this year and Toyota and Honda expanding their vehicle lineups, the hybrid trajectory is distinctly up.