NEW YORK—New York Mayor Michael Bloomberg and officials in the Long Island counties of Nassau and Suffolk have decided to start an even-odd gas rationing plan beginning at 5 a.m. Friday.

The plan means that gasoline will be available to drivers with licenses plate numbers ending in an odd number Friday, which is Nov. 9.

Saturday will begin days for gas services for drivers with plate numbers ending in an even number.

Bloomberg says at a briefing that only 25 percent of the city's gas stations are open. He estimated the shortage could last another couple of weeks.