U.S. trucking will remain plagued with equipment and driver shortages this year, according to an industry trade group.

Though freight growth is slowing from last year’s pace, it “is leveling off at a very high level, and in some sectors it can continue to grow,” said Bob Costello, chief economist for the American Trucking Associations.

The industry is short about 80,000 drivers even as pay has jumped, and truckmakers can’t keep up with demand, he said in an interview. “Supply remains challenged this year in the trucking industry, even if we do add some more drivers.”

For customers, that all adds up to ports remaining congested as manufacturing rebounds, companies seek to rebuild inventories and consumers continue to spend at high levels. Spot freight rates—which rose 29% last year, according to KeyBanc Capital Markets—will likely remain elevated.

But new entrants who paid “outrageously high” prices for used equipment could face a shock at some point, Costello said.

“I am worried about what happens to those folks when we get out of this environment of really tight capacity and booming freight,” he said. “You could see a lot of capacity exit this industry in the next downturn.”