Ziggy Duchnowski spent Saturday morning car shopping along Northern Boulevard in Queens with two goals in mind.

He wanted to find a new small car for his wife, and he hoped to strike a deal before the new tariffs that President Trump is imposing on imported cars and trucks affect prices.

“The word on the street is prices are going to shoot up now,” said Mr. Duchnowski, 45, a union carpenter who voted for Mr. Trump, holding the hands of his two small children.

The tariffs — 25 percent on vehicles and parts produced outside the United States — will have a broad impact on the North American auto industry. They are supposed to go into effect on April 3 and are sure to raise the prices of new cars and trucks.

They will also force automakers to adjust their North American manufacturing operations and scramble to find ways to cut costs to offset the tariffs. And for now at least, they are spurring some consumers to buy vehicles before sticker prices jump.

Analysts estimate that the tariffs will significantly increase the prices of new vehicles, adding a few thousand dollars for entry-level models to $10,000 or more for high-end cars and trucks. Higher prices for new vehicles are also likely to nudge used-car prices higher.

Every automaker will feel some kind of impact. General Motors builds a large number of highly profitable pickup trucks and sport utility vehicles in Canada and Mexico. Toyota and Honda make popular S.U.V.s in Canada. Volkswagen assembles the Jetta sedan, Tiguan S.U.V. and other popular models in Mexico.

“Once the tariffs go into effect and people start receiving quotes that represent these 25 percent increases, that’s when it’s going to start to sink in,” said Bill Pacilli, the sales manager at Lynnes Hyundai in Bloomfield, N.J.

Close to half the cars that Hyundai sells in the United States are imported from South Korea, he said. “They’re going to be hit with the tariffs in about a month or two,” Mr. Pacilli said. “Of course we’re concerned. Any effect in pricing is going to affect sales volume.”

While many dealers did not see a noticeable increase in buyers on Saturday, Jeremy Gleason, general manager at McGrath Subaru Evanston in Skokie, Ill., said his dealership had its biggest sales day since it opened in 2021.

“It’s been nuts,” Mr. Gleason said. “The tariffs have come up a lot and pushed people to move forward quicker.” He added that his dealership typically sells about 15 cars on Saturdays but sold 32 on this one.

Alvaro Duarte, an Ecuadorean immigrant who lives in West New York, N.J., went to Hudson Toyota in Jersey City, N.J., on Saturday to trade in his gas-powered car for an electric model, fearing prices would rise if he waited.

“Tariffs affect everyone,” said Mr. Duarte, 37. In his free time, he said, he often uses his car to earn money on the side as an Amazon Flex delivery driver. “If the prices go up, I need to pay more for my car, and that’s more expensive for me and my family,” he said. “I made the change because with electric cars there is no gasoline and less maintenance.”

Meanwhile, a salesman at Audi Manhattan in New York, Abdul Azeez, said traffic was no brisker than usual, and suggested it was because the people who live in the neighborhood usually have the means to buy new cars whenever they choose.

“Overall, I don’t think dealers in Manhattan are going to be as affected compared to dealers in other states or less busy cities, because even in the good economy, bad economy, there’s always going to be somebody who walks in the door to buy a car,” said Mr. Azeez, 24.

In Ann Arbor, Mich., on the strip of auto dealerships west of downtown on Jackson Avenue, customer traffic was pretty normal for a Saturday on the last weekend of the month — typically a busy time.

But a Tesla showroom drew a crowd: some 300 to 400 people gathered to protest the political activities of the company’s chief executive, Elon Musk.

Mr. Musk heads the cost-cutting initiative known as the Department of Government Efficiency, which has eliminated thousands of federal jobs and gutted several government agencies, including the Veterans Affairs Department and the Education Department.

Protesters carried signs calling for Mr. Musk’s firing and urged people to sell their Teslas.

“We’ve got to get some basic common sense back in this country,” said Harold Blake, 73, a retiree who drove 30 miles from Dearborn to participate in the protest.

“It’s so extreme, what’s going on in Washington,” he said. “I’m not taking it lying down.”

Over the course of an hour, no customers crossed the picket line to enter the Tesla showroom.

Protests were taking place at Tesla locations around the world, as part of the so-called Tesla Takedown movement. More than two dozen such demonstrations were scheduled across the United States on Saturday. Others were planned for Europe, Australia and New Zealand.

“I’m terrified for my kids and grandkids for what this world is coming to,” Kathy Sinnes, 67, said while protesting outside a Tesla showroom in Miami and holding a poster that read, “Tesla greed we will not heed.”

It remains unclear how soon prices on new vehicles will rise. Most automakers have enough tariff-free cars and trucks on dealer lots to last 60 to 90 days.

Juan Carlos Fagerlund decided not to wait. He was in a Toyota dealership in North Miami, Fla., to add window tinting to a Prius he had bought this month.

Although he had already been thinking about buying a new car, he said, the potential of higher prices prompted him to speed up his shopping, especially because he wanted a Prius. The car is made in Japan and will be subject to a heavy tariff.

The tariff increase “was not entirely the reason why we purchased in March,” Mr. Fagerlund said. “But it was definitely in our minds.”

Adria Pina, 60, a Dominican immigrant and a New Jersey Transit bus driver who lives in Bayonne, N.J., also decided to move quickly. Sitting in the Hudson Toyota dealership in Jersey City minutes after she bought a new car, she said she felt that she had just dodged a tariff pothole.

“My husband said we got lucky that we got a deal right before the tariffs,” Ms. Pina said. “If we didn’t get this done in time, it would have cost us about $10,000 more. That’s a lot of money.”

Sal Sellers, 57, the general sales manager at Hudson Nissan next door, didn’t seem overly concerned about the looming tariffs, noting that he had been through the pandemic and other serious economic downturns. But that didn’t mean his customers weren’t worried.

“Last week, we had a couple customers walking in saying: ‘You know what, I’m not waiting. I’m going to change my car now before the tariffs hit,’” Mr. Sellers said. “I’d say about 30 percent of my customers said that.”

Outside Chicago, Enzo Costa oversees eight dealerships as director of sales for the family-owned Patrick Dealer Group.

In March, he said, he increased his orders for new cars to top off his inventory before prices rise, and his acquisitions team purchased 30 used vehicles — about three times the usual number.

So far, though, he hadn’t seen a spike in customer traffic. “On a normal Saturday, we set 80 to 100 appointments,” he said. “Today, we have 75.”

He added that his sales team was urging customers considering new cars to come to the showroom. “Everything in inventory is pre-tariff,” he said. “You don’t have to worry about that now. That’s something that is way down the road.”

At Silver Line Auto Group in Queens, which sells used Jeeps, Cadillacs and Mercedeses, many customers are immigrants or other people who have driver’s licenses but not Social Security numbers. Back in December, Silver Line sold 35 cars, but business had crashed since then, said a salesman, Silver Bautista. The company sold just eight cars this month and recently laid off four employees.

Mr. Bautista said he believed that customers were staying away not because of rising prices but because they felt a need to save money.

“They don’t care about tariffs,” Mr. Bautista said. “People are worried about being deported.”

Robert Chiarito, Ryan Hooper, Verónica Zaragovia, Anusha Bayya and Nate Schweber contributed reporting.