Travelers using LaGuardia Airport can get a free bus ride or free parking as officials try to ease an expected traffic mess during the pre-Christmas holiday rush.

Most transportation hubs will be busy during the holiday season, but traffic on LaGuardia’s access roads has been difficult for the past six months during the initial stages of a multibillion-dollar reconstruction of the entire airport.

The Metropolitan Transportation Authority said it will offer free rides Thursday and Friday on its Q70 express bus to LaGuardia from the Long Island Rail Road station at Woodside and the subway station at 74th Street in Jackson Heights.

The Port Authority said it would provide free parking Friday at Lot P10, which connects to the passenger terminals by free shuttle buses. The free parking is on a first-come, first-served basis.

Parking is usually $39 daily at Lot P10, but it was cut to $18 between Thanksgiving and New Year’s in an effort to ease congestion at the terminals as the airport is under construction.

“Friday is expected to be the busiest day of the holiday travel season at the airport,” the Port Authority said in a statement.

advertisement | advertise on newsday

Anyone hoping to get a jump on other travelers by leaving Wednesday might have gotten a jolt when traffic in the airport’s traffic lanes got clogged Wednesday morning and backed up on the adjacent Grand Central Parkway.

“Due to a disabled vehicle, there is heavy traffic on terminal roadways. Please allow extra travel time . . .” LaGuardia Gateway Partnership, which is rebuilding the central terminal and airport roadways, said in an advisory about 6 a.m. Wednesday.

A later advisory about 10 a.m., and other advisories during the day, said traffic on the airport roads was light to moderate.

“The holiday season is upon us, and we expect LaGuardia Central Terminal B and the entire airport to be busy — especially as our multibillion-dollar redevelopment project is underway,” another advisory from the developer said.