In at least one little corner of the world, the fight for green taxis is over. In the environmental mecca of San Francisco, 85 percent of all taxis are hybrids, seven to eight percent run on compressed natural gas, and another eight percent are conventional vans that offer wheelchair accessibility.

Paul Gillespie founded and the California Clean Cab Partnership, and served as president of San Francisco’s taxi commission until 2009. A taxi driver himself, it’s safe to say he knows green cabs. Gillespie says his experiences during the 1973 oil embargo are what led him to the pursuit of more environmentally friendly options for the taxi fleet.

“My main focus is cutting greenhouse gas emissions in half by replacing all the gas-guzzling Ford Crown Victorias with efficient hybrids,” he told me.

That work is well underway. The cleaner taxis alone have already reduced San Francisco’s greenhouse gas emissions by more than 20 percent below 1990 levels and more than 50 percent below 2005 levels in three years, Gillespie says. That’s a cut of more than 50,000 tons of carbon dioxide, which is actually greater than the 40,000 tons saved by the city’s other efforts, which include a high-efficiency lighting program, solar panels on the Moscone Center and weatherization efforts.

The climate progress isn’t just a fringe benefit, it’s the law. As an unpaid taxi commissioner in 2008, Gillespie wrote the law that required greenhouse reductions of 20 percent below 1990 levels by this year. “This is more significant than it sounds since our fleet size has more than doubled since 2008,” he said.

Look at those numbers! The taxi fleet emitted 70,000 tons in 1990, and 110,000 tons in 2008. But it’s only 41,000 tons in 2012. “We’ve doubled the size of the fleet and cut emissions in half, putting thousands of dollars in the pockets of hard-working cab drivers,” Gillespie says. San Francisco’s hybrid taxis weren’t built with fare service in mind—they’re regular cars, including the Toyota Prius, Ford Escape and Nissan Altima.

Gillespie says that Ford and Toyota were originally not convinced their cars would make good taxis. “Our fleet of Escape taxis, put into service in November of 2004, weeks after the vehicle appeared, took many at Ford by surprise,” Gillespie says. “It wasn’t until over a year later when Mayor Bloomberg went on the Today show with Bill Ford and said he was going to convert the fleet to hybrid that some credibility was established.”

What’s happening in San Francisco is quite a contrast to New York City, which has a large hybrid taxi fleet now (thanks to the enthusiastic support of Mayor Michael Bloomberg) but because of lawsuits is switching to Nissan’s non-hybrid “Taxi of Tomorrow” (at right, in Manhattan).

As Gillespie points out, the NV200 isn’t a hybrid, and there’s only vague talk of an electric version appearing sometime down the road. Bloomberg is an enthusiastic hybrid backer, but his hand was forced by a series of unfortunate lawsuits that challenged the city’s right to switch to an all-green fleet.

As the Harvard Law Review described it, the city lost a lawsuit contending that its right to set taxi policy was pre-empted by the federal Energy Policy and Conservation Act (ECA), which authorized the federal Corporate Average Fuel Economy (CAFE) rules. Those now require auto fleets to reach 54.5 mpg by 2025, but they don’t let municipalities like New York set their own fuel economy rules. The same argument has been used—unsuccessfully—to challenge California’s global warming law.

California won on something of a technicality, because it set climate emission rules, not fuel economy standards. The two have pretty much the same result (your fuel economy determines your CO2 emissions), but not legally. There haven’t been any challenges to Gillespie’s 2007 mandate, at least so far. Visitors to Boston, New York (left), Vancouver, Philadelphia and many other cities can see that hybrids are winning the battle for the streets, even in the absence of specific mandates. In the form of the Prius, they’re also a mainstay in Tokyo.

Taxi drivers, and owners usually, just like saving all that fuel. And the cars have proven very dependable on the road, too, with some San Francisco cars hitting 300,000 miles on a single set of batteries. The hybrid taxi is here to stay.

Just for the hell of it, I've added this wild animated police car chase through the streets of San Francisco. And, yes, that is a taxi they're following (not a hybrid, I don't think):

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

I left my hybrid taxi in San Francisco
California's City By the Bay has dramatically cut greenhouse gas emissions by switching to a mostly hybrid taxi fleet. It's a model for the rest of the country.