SEATTLE -- Seattle Mayor Greg Nickels said Wednesday he would like all the taxis in the city to be “green” by the year 2013.

That means every current cab owner may eventually have to replace their taxi with a more fuel-efficient vehicle.

Many cab drivers said they aren’t happy about the idea.

Most of the cabs currently in Seattle are roomy Ford Crown Victorias.

“It’s a very good car, I think,” said cab driver Hussein Farah.

Seattle's mayor said the taxis guzzle gas, averaging 18 miles per gallon and pump tons of carbon into the air, which contributes to global warming.

“We think they should all be green,” said Nickels, who proposes that any new cab should get at least 30 miles per gallon.

“That simple step will reduce the greenhouse gas emissions from the current fleet by 40 percent,” said Nickels.

The mayor said he’s hoping that cabbies will opt for even more fuel efficient vehicles like the Toyota Prius and said the fuel savings alone should more than make up for the cost of a new car.

Cabbies said they are taking issue with both the mayor's math and his understanding of their business.

“The cost of the vehicle is so high. The driver can’t afford that much,” said Seattle cab driver Gurminder Kahlon. “The Crown Victoria is a very safe car and it’s very dependable.”

Many Crown Victorias are former police cars that can be purchased for $5,000 to $7,000 and have plenty of room for passengers and luggage.

“We need more space and more trunk (room),” said Kahlon.

Cars that get at least 30 miles per gallon are generally smaller and lighter than the Ford, and though the Prius has a relatively roomy interior, it costs $28,000 fully equipped as a cab.

The mayor also wants to increase the number of taxi licenses in the city as well as regulate the rates that taxi license holders charge taxi drivers. The mayor's proposal is set to go before the city council.