The yellow cabs of New York City will soon be green — if not in actual color, then in their eco-friendliness.

The city wants all of its 13,000 taxicabs to be converted to hybrid electric engines by 2012. Mayor Michael Bloomberg says New York air will be cleaner and the city will save 22 million gallons of gasoline a year when all its taxis are hybridized.

At present, only 385 of Gotham's famed yellow taxicabs use hybrid engines. These include Toyota Prius, Ford Escape, Toyota Highlander and Lexus RX 400h models.

Most of the remainder cabs are Ford Crown Victorias, a fullsize sedan favored by taxi drivers and police for their roominess, V-8 power and rear-drive transmission location.

Toyota has disclosed interest in expanding sales to U.S. taxi fleets and police departments, pointing to better fuel economy and emissions reduction offered by its hybrid vehicles.

However, the Japanese auto maker has been handicapped in its effort to dislodge the Crown Victoria from its dominant role as a taxi and patrol car by the fact that Prius and Camry hybrids are less roomy than the Crown Vic and the location of their transmissions in front causes increased maintenance expenses where police cars are more apt to run over curbs.

Hybrid Prius and Escape police vehicles are in use in Boston, San Francisco and Vancouver, BC.

Toyota declined comment on reports that it is fitting out its fullsize Avalon with a hybrid engine as a police offering that could rival the Crown Vic's roominess.

Ford, for its part, is seeking to protect its 80% share of the police vehicle market with plans for a Crown Vic with a turbo-diesel engine, insiders say.