People stop along the Brooklyn waterfront to photograph the Brooklyn...

People stop along the Brooklyn waterfront to photograph the Brooklyn Bridge and the Manhattan skyline in New York. Much of lower Manhattan is without electric power following the impact of superstorm Sandy. (Oct. 30, 2012) Credit: AP

All major bridges to Long Island reopened at noon Tuesday -- with the exception of those in the Rockaways, Gov. Andrew M. Cuomo announced.

New York City's Holland and Hugh L. Carey Brooklyn Battery tunnels will remain closed, Cuomo said.

Cuomo spoke during a late morning briefing during which he announced that Kennedy Airport in Queens could open as early as Wednesday. LaGuardia Airport won't open as soon because of "extensive damage" that includes runway flooding.

After all bridges and tunnels connecting the Island to New York City were closed due to Sandy, Mayor Michael Bloomberg announced Tuesday afternoon the East River crossings were reopened.

All state parkways north of Merrick Road in Nassau and Montauk Highway in Suffolk reopened at noon Tuesday.

Nassau County police said the Long Island Expressway was closed in the county -- and County Executive Edward Mangano said all county roads were closed, as well. The Suffolk County Sheriff's Office said the LIE was open in Suffolk, as was Sunrise Highway. Suffolk police said there were no significant road closures, though authorities in both counties made it clear flooding, downed trees and downed power lines were impacting myriad roads -- causing random closures.

Drivers had to contend with nonfunctioning traffic signals at thousands of intersections islandwide. Police also emphasized drivers should follow a driving basic: When traffic signals are out, intersections are, by law, considered to be governed by a four-way stop.

All vehicles must stop. And that all vehicles must heed the right of way as governed by state vehicle and traffic law.

Suffolk County Department of Public Works Commissioner Gil Anderson said that county roads were open, with the exception of some lanes in places where trees were down and responders were awaiting line crews to handle downed wires before they could remove the fallen tree limbs and debris.

"Our No. 1 priority is getting the linesmen out there so we can move forward," Anderson said, adding extreme care was still needed on the roads.

Earlier Tuesday morning, Cuomo announced the following MTA bridges would reopen to emergency personnel only: the Robert F. Kennedy / Triborough, Throgs Neck, Bronx-Whitestone, Verrazano-Narrows, Henry Hudson, Marine Parkway-Gil Hodges Memorial and the Cross Bay Veterans Memorial.

In a phone-in interview on WNBC-TV early Tuesday, Cuomo said: "We have teams assessing the bridges and the condition of the bridges now, and my guess is we will start to open up some bridges, first for emergency personnel and then let's see how it goes through the rest of the day. The roads should be avoided. They really should be avoided. The tree damage. The leaves. The water. Many of the roads are still blocked with trees. We have crews all over the metropolitan area. We will be doing openings, but I will strongly advise people, unless you really have to go out for something important, this is another day to stay home and let the crews do their work."

Citing wind gusts of 100 mph, Cuomo had ordered the RFK / Triborough Bridge closed Monday. As the storm reached its peak, Bloomberg ordered all East River bridges closed.

As of 8:45 p.m. Monday, all MTA bridges and tunnels were closed, leaving Long Island an island -- cut off from all points north, west and south.

Coupled with the closure of the Long Island Rail Road, all mass transit, all major area airports and all ferry service, and massive power outages, caused the truest-sense isolation.

Affected parkways included the Southern, Northern, Meadowbrook, Ocean, Loop, Wantagh, Sagtikos-Sunken Meadow, Robert Moses and Bethpage. Earlier Monday, rain and winds from the hurricane had already forced the closure of many roads in Nassau and Suffolk, including all parkways south of Merrick Road and Montauk Highway, and stretches of Montauk Highway from Babylon east to Montauk.

State police spokesman Frank Bandiero said New York State Department of Transportation crews worked through the night to clear downed trees from most parkways, but said residual debris, flooding and ponding were still causing roads to be closed.

He said police were "hopeful" most parkways would be reopened sometime Tuesday morning, but said affected north-south parkways would likely remain closed south of Sunrise Highway due to flooding -- and, he said, it was uncertain when that would change.

With John Hildebrand and Deborah S. Morris