“We don’t think that the rate of growth of S.U.V.s will necessarily continue, but we do believe the shift to them is permanent,” said Mike Manley, head of Fiat Chrysler’s Jeep division.

Pickup trucks and S.U.V.s have accounted for about 62 percent of all new vehicles sold in the United States so far this year, compared with 57 percent in the first quarter of 2016, according to the research firm Autodata.

That extends a trend line that has inched upward since gasoline dropped below $3 a gallon in 2014.

The big American auto companies have been the greatest beneficiaries of the public’s appetite for high-riding, spacious S.U.V.s, which generally earn bigger profits for manufacturers than mainstream cars.

In March, more than 70 percent of the vehicles sold in the United States by General Motors and Ford Motor were trucks and S.U.V.s. The proportion was even higher, about 85 percent, for Fiat Chrysler.

All three Detroit automakers and their foreign rivals are working overtime to add new or updated sport utility vehicles to their lineups.