Spurred by lower gas prices, 43 million Americans, including 3.1 million New Yorkers, will travel this Independence Day weekend, AAA predicts.

It would be the highest Fourth of July travel volume on record and 5 million more travelers nationwide than during the Memorial Day weekend, the motorist group said.

Travel over the four-day weekend, from Thursday to Monday, will be up from the 41.9 million who traveled — defined as taking a trip of more than 50 miles — at this time last year, AAA said.

Nationally, the price of a gallon of regular-grade gasoline is about $2.32, or 48 cents less than it was a year ago, AAA said. On Long Island, a gallon averages $2.46, down 56 cents from a year ago, AAA said.

The Port Authority of New York and New Jersey said it expects about 2.6 million passengers will use its regional airports — with Kennedy, LaGuardia and Newark Liberty accounting for most of the traffic. That would be a 2.3 percent increase over last year’s holiday weekend.

The Transportation Security Administration, criticized for long screening lines earlier this year, said in a Twitter message that it expected passenger volumes “to drastically increase” this weekend, but it did not elaborate.

This will also be a test for travelers using LaGuardia, where a $4 billion redevelopment of the main terminal and other facilities has just begun.

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“Parking at LaGuardia will be aggressively managed throughout . . . the project that will require the closure of some lots, but travelers should leave extra time and use public transportation, if possible,” the Port Authority said Wednesday.

Also, the TSA reminded air travelers that fireworks are prohibited in both checked and carry-on luggage.

For Long Islanders staying home, or close to it, the National Weather Service said there might be showers Friday, but it should be sunny or mostly sunny through the weekend and into the Monday holiday.

“Right now, the forecast is looking good for Jones Beach, and for parks,” George Gorman Jr., deputy regional director for the state Parks Department, said.

“We anticipate good crowds,” he said, estimating that about 200,000 visitors are expected at Jones Beach on Monday, the holiday, and about 100,000 for the fireworks show that night.

“For the fireworks, we will have an additional law enforcement presence and expanded security screening to include the east and west bathhouses, in addition to the central mall, so after individuals park, they will be screened,” Gorman said.

The parks system is bracing for the usual traffic jam at Sunken Meadow State Park on the North Shore, and has its annual plan in place to start diverting motorists to Heckscher State Park when the Sunken Meadow lots start to fill up, Gorman said.

The Long Island Rail Road added eastbound trains for Friday afternoon, and said it would have extra service over the weekend to the East End of Long Island.

All nonemergency road and bridge work in the region was postponed for the weekend.

Finally, AAA reminds motorists to check their cars, particularly the battery and tires, before any trip.

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AAA said it expects more than 370,000 requests for roadside assistance during the weekend, and historically the primary reasons will be a dead batteries, flat tires and lockouts.