LOS ANGELES — President-elect Donald Trump’s threatened tariffs on top trade partners China, Mexico and Canada would deal a blow to the $1.7 trillion U.S. transportation industry and worsen a nearly three-year trucking recession, sector experts said. The industry that moves everything Americans make and buy is considered an economic bellwether, and will be among the first to signal any unintended consequences of trade policies that Trump says will help, not hurt, U.S. businesses. …Virtually every transportation company operating in the United States is exposed to tariff-related revenue downturns. …Trump’s new tariffs on Mexico and Canada, in particular, would hit one of the rare growth areas for trucking. The value of cargo that moves between those countries and the U.S. – which includes finished vehicles, auto parts and avocados from Mexico as well as steel and lumber from Canada – reached $88.5 billion in September 2024, up 7.7% from the year-earlier.