DETROIT—Trump administration demands in NAFTA trade negotiations meant to push auto jobs back to the United States may not be enough to spark a shift in where automakers build cars and trucks.

New math to determine what qualifies as vehicle content, what limits apply to allow tariff-free auto imports and how long companies would have to comply under a new NAFTA agreement will likely not move the needle for Detroit automakers in particular, industry executives and supply chain experts said.

Automakers are unlikely to uproot billions of dollars of investments in plants and supply chains. And those that cannot comply with standards for passenger cars could simply pay tariffs of around $800 to $900 per vehicle and buy low-cost parts from Asia to offset the cost, industry experts said.