The Fourth of July holiday weekend may not officially start until Friday, but as usual, the explosions that mark America’s birthday begin early, and this year, the big boom of travelers is expected to get moving Thursday and run through Monday.

Long lines of passengers again are expected to snake through Bay Area airports, and drivers will be getting up close with each other, bumper to bumper.

“It’s the peak travel period for the whole year,” San Francisco International Airport spokesperson Doug Yakel said. “Higher than Thanksgiving. Higher than Christmas. Add to that you have the holiday falling on a Friday, and you can get an idea of what it might look like.”

What it likely will look like is chaos — appearing organized, perhaps, but wild nonetheless.

“When you see the Fourth fall on that odd day in the middle of the week, it usually limits people’s activities,” California Highway Patrol spokesperson Sgt. Andrew Barclary said. “When it’s on a Friday, it’s quite the opposite. So this weekend, we’re planning for a large amount of travel.”

Here’s how chaotic it may be: According to AAA, more than 8.9 million Californians are expected to travel on the road or by air at least 50 miles from June 28 through July 6. That’s the period that traditionally receives the holiday lift, according to the company. The number will be an increase of nearly 182,000 people from the same period in 2024.

AAA also projects 1.2 million California residents will fly somewhere, about 24,000 more than a year ago. Locally, about 1.07 million people are expected to come and go through the Bay Area’s three major airports starting Thursday and running through Monday.

Yakel said 800,000 passengers are projected to go through San Francisco International Airport. Port of Oakland spokesperson Kaley Skantz said about 125,000 passengers will go through Oakland International Airport. At San Jose Mineta International Airport, spokesperson Julie Jarratt said approximately 82,000 passengers will depart and arrive.

One bit of good news for those passengers; the first Fourth of July in the REAL ID era does not appear to be the line-stopper it initially was projected to be be.

“Since the implementation in May, we have not seen significant delays, no excess lines,” Jarratt said. “For the most part, people have been compliant. Or they have a passport, which works just as well.”

Yakel said that for those without REAL ID or a passport, a-non REAL ID compliant drivers license or state identification card can suffice. Those passengers will be subject to an additional verification process that will slow down their progress getting past the TSA inspection.

“It’s not been a big deal,” Yakel said. “The TSA is letting people travel who don’t have it, but obviously, those people will be slowed down quite a bit. From a customer standpoint, it’s a good thing. We don’t anticipate it affecting many people. We’ve had a 93% compliance rate since the implementation.”

The airports advised passengers that they should arrive three hours before their flight, rather than the standard of two hours, and that they can reserve parking at their locations ahead of time via the airport websites. Cell phone lots — set aside for drivers waiting for passengers to arrive — are expected to fill quickly, so arrive early to pick up your passenger, officials said.

On the freeways, California can expect to see 7 million people on the roads, an additional 1.3 million people from a year ago, according to AAA.

“I think we see people leaving already,” Barclay said Monday afternoon. “That could end up being a good thing. There may be more of a trickle effect than when everybody heads out at once.”

Gas prices, usually higher at this time of year in California, averaged $4.58 a gallon in the state as of Tuesday, according to AAA’s survey, well over the national average of some $3.18 a gallon but more than 20 cents lower than the state average at this time last year.

Barclay said the CHP will have additional patrol units out to look for reckless drivers and those who may be driving under the influence. He encouraged drivers to slow down, because there is not likely be any place where the lanes open up for long stretches at a time.

And during those quick stops for food, gas and nature — don’t leave a baby, small child or pet behind in a small car, he said.

“The vehicle can exceed 100, 120 degrees in just a couple of minutes, even in 80-degree weather,” Barclay said. “It’s just not a good idea ever to leave somebody alone in a car.”

The same extra care should apply to those trying to sneak in a drink or two with alcohol and then going on their way.

“There’s always the DUI component,” Barclay said. “And we say it every year but can never say it enough. If you’re celebrating, designate a sober driver.”

That message went out for boaters, too, along with a warning to make sure that anyone on the water should be wearing a life vest. Authorities also advised people to keep an eye on the weather for sudden changes, especially in the aftermath of the boating tragedy in Lake Tahoe last month. Eight people died when the weather suddenly turned foul, turning the lake into a mini-ocean.

The drive to Tahoe may be particularly packed. Construction projects on Interstate 80 near the Highway 50 split slow traffic in that area considerably on a normal day, and according to Caltrans, the lane restrictions will hold even when workers are enjoying the holiday.

The weather is expected to cooperate. Sunny weather that will peak in the mid-80s in the hottest places is forecast for the Contra Costa, Alameda and Santa Clara counties, while the coastal cities are expected to hover in the 60s. Lake Tahoe is expected to peak at 70 degrees on the Fourth.