Hybrid cars are all the rage in the San Francisco Bay area. About one in five hybrids sold in the U.S. has been purchased in the Bay area, and the average waiting time to buy a Toyota Prius or Honda Insight is five months at local dealers. Drivers say heads turn as their cars cruise by; some folks even talk of the sex appeal of the vehicles. In related news, across the U.S., about 37 percent of people in the market for a new vehicle in 2001 considered themselves “extremely concerned” about the environment — more than triple the percentage who said they had that level of concern in 1996. Still, alternative-fuel vehicles have made up only 50,000 of the 16 million vehicles sold in the U.S. this year.