Foreign-born truck drivers may need to bone up on their English-language skills by June 25. That’s when authorities have the green light to bar holders of commercial driver’s licenses from the road because they don’t have a sufficient grasp of the language.

Large trucking companies, which normally decry driver shortages, have been pushing for this change, citing safety reasons. The Trump administration was more than happy to rescind a 2016 directive by the Federal Motor Carrier Safety Administration that suspended the lack of English-language proficiency as a reason for putting a driver out of service.

“America First means safety first,” Transportation Secretary Sean Duffy said when he signed the order during a May 20 event in Austin, Texas. “Americans are a lot safer on roads alongside truckers who can understand and interpret our traffic signs.”

There is no conclusive data that drivers who don’t speak English are more dangerous. Proponents point to a few anecdotes of accidents caused by non-English speakers among the tens of thousands of big-rig crashes that occur every year involving drivers who speak the language. The zeal to enforce the language proficiency rule, which has been on the books forever but was unevenly enforced before the 2016 directive, is all about reducing trucking capacity in an industry that is suffering through an unprecedented slump of more than three years.

The problem with pinning the action on safety is that when the industry does recover and hits an upcycle, the trucking companies will return to lamenting the shortage of drivers and won’t be able to recruit drivers who have limited English skills. One can’t argue that these drivers are dangerous during a downturn but just fine during a bull market. The number of drivers potentially put out of service could be large. In 2015, more than 99,000 drivers had English-language-proficiency violations, and only 1,000 of them were taken out of service, Duffy said during the Austin event. After the 2016 directive, the number of such violations dropped to 10,000 last year, and no licensed drivers were removed from the road.

This move to reduce drivers is understandable because trucking companies and investors have been waiting impatiently for the industry to shed capacity, which is typical for the highly cyclical freight market. The usual rebalancing of the supply and demand didn’t take place in the post-pandemic cargo recession. Some of the reasons cited for drivers sticking around longer than in past downturns are the federal stimulus payments aimed at small companies and the outsized driver earnings during COVID-19, when freight rates soared. That cushion should have run out. Another reason being floated is that there has been a large influx of foreign-born drivers who are willing to live out of their truck sleeper cabs and scrape by on meager earnings.

In a separate push to reduce capacity, large trucking companies are urging authorities to crack down on drivers from Mexico and Canada who aren’t supposed to pick up and deliver loads within the U.S. This point-to-point transportation, often called cabotage, violates the visas that only allow these drivers to bring a load into the U.S. from their country and pick up a U.S. load to take back home. Stepped up enforcement of cabotage makes sense because these Canada- and Mexico-based drivers have never been allowed to provide service within the U.S., just as U.S. drivers can’t haul freight within Canada or Mexico.

Cracking down on cabotage could have a greater effect than enforcing the language requirements, Nick Hobbs, chief operating officer at J.B. Hunt Transport Services, said during a Wells Fargo conference this week. Enforcement of trucking regulations falls mostly to state and local officials, which means that increased inspections would likely be more acute in “red states,” he said. Hobbs said he’s encouraged about a trucking turnaround based on expectations that a peak season for freight will occur this year despite tariffs and that stricter enforcement of language skills and cabotage will reduce capacity.

“There’s a lot of different noise, different things going on that maybe gives us a little bit of optimism that maybe some things are happening on the supply side that might be going away a little bit,” he said.

Hobbs and other trucking executives may change their tune when the freight market tightens, and drivers become scarce again. Trucking companies likely will want to hire more of those people who drive much better than they can speak English.

Thomas Black is a Bloomberg Opinion columnist writing about the industrial and transportation sectors. He was previously a Bloomberg News reporter covering logistics, manufacturing and private aviation. This column reflects the personal views of the author and does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.