MANHEIM, PA — Surrounded by the quiet corn fields of Pennsylvania's Amish country are 400 acres of paved lots packed with used cars that make up the world's largest used auto auction here.

The voices of dozens of auctioneers across 36 lanes simultaneously rattle off prices, makes and models in a rhythmic repetition. "SOLD!" is cried out with each purchase — at least once every 60 seconds, 500,000 times a year.

The prices at the Manheim auto auction have been better than usual lately, especially since President Donald Trump started pushing for new tariffs on imported vehicles, parts as well as the steel and aluminum used to make cars, said Jonathan Smoke, the chief economist of Cox Automotive. Cox runs the auction, which draws dealers from around the country to bid online or in person at the auction house.

Smoke tracks three-year old vehicles as an indicator of pricing for used cars, since that's when a lot of leases are turned in and that vintage is the most common pre-owned vehicle for sale at any given time. A three-year-old Nissan Altima costs about $100 more now than it did just last month. A three-year-old Toyota Camry costs $400 more than it did a year ago.

"The fact this happened almost exactly two weeks after Trump announced he was going to enact tariffs can't be ignored," Smoke said, referring to tariffs Donald Trump has proposed on new vehicles imported to the United States.

The Manheim Used Vehicle Value Index, increased 5.1 percent in July over the same month last year. July used car prices were also up 1.5 percent over the June prices, and the index is at its highest point since it first started tracking used sales in 1995.