If you're lucky, as I have been in several cities, you might occasionally flag down a rare taxicab bedecked by its driver with disco balls, mood lighting, tinfoil hearts, or even a menagerie of stuffed animals. This week, San Franciscans got the option to hitch a ride in a novelty taxi of a different sort, as start-up Green Cab's single hybrid Honda Civic hit the road. Next month the fleet could total five gas-electric taxis painted in low-toxic green paint.

"It's not only environmentally friendly, it's good financially for the driver," said Green Cab co-founder Thomas George-Williams. Fuel for the hybrid Civic costs $8 per shift, a fraction of the $45 to quench a gas-guzzling Crown Victoria, he said.

Mark Gruberg and Thomas George-Williams high-five their launch of Green Cab.

(Credit: Green Cab San Francisco)

Eight taxi drivers who wanted to improve their working environment while providing an ecofriendly service launched Green Cab, which provides them workers' compensation and will soon offer health insurance. Thirty drivers have joined the hiring wait list. George-Williams said he hopes to establish a model for other cities.

Green Cab is the latest sign of the growing greening of taxi, limousine, and rental-car services around the country. Some 180 hybrid and natural gas taxis currently roll the streets of San Francisco, where Mayor Gavin Newsom wants all cabs to have alternative fuel systems by 2010. Yellow Cab and Luxor Cab introduced hybrid Ford Escape SUVs to their fleets here in 2005. And since New York City taxi companies followed suit later that year, Treehugger.com has reported that hybrid riders tend to tip better.

But George-Williams isn't worried about competition from larger cab services. "They can't call themselves green because they're yellow," he joked.

For those who like to ride in style, ecofriendly chauffeur services are also on the rise. Bauer's corporate limo services are expanding nationally from their core green service, shuffling around Google employees in luxury electric and natural gas limousines. The Eco Limo operates in Los Angeles, San Francisco, New York, and Washington, D.C.; Vail, Colorado, visitors can sip organic beer and wine inside a posh, biodiesel Ford Excursion airport ride from Green Limousine.

Travelers looking to get behind the wheel while lessening their carbon footprint might pick a gas-electric Civic, Toyota Prius, or Highlander from EV Rental in six California cities and Phoenix, Arizona. Competitor Fox has hybrids in most of those cities as well as in Florida and Colorado. Tourists can zip around Maui or Los Angeles in a biodiesel Volkswagen rented from Bio-Beetle. The ever-expanding car-sharing companies Zipcar and Flexcar offer hybrid models that members can rent by the hour in more than a dozen cities.

Large car-rental corporations are slowly going green as well. Enterprise offered biodiesel options last year to customers in Portland, Oregon, and is introducing Saturn hybrids to three California cities. Avis and Hertz have focused on adding tens of thousands of vehicles that achieve at least 28mpg, about half the touted urban efficiency of a Prius.

And for when that rental car--green or not--breaks down, the Better World Club pitches itself as an ecofriendly foil to AAA and offers help for those stranded with an auto or a bicycle.