WASHINGTON — U.S. Transportation Secretary Sean Duffy moved to codify English proficiency requirements for commercial truck drivers, a change that would end a system allowing driver's license exams in up to 20 languages.

"When a driver cannot read a critical road sign, people die," Duffy said, framing the rulemaking as a road safety measure. The proposal would make English the sole language for all commercial driver's license testing, including written and practical components.

Under the current framework, applicants in some states — California among them — can complete CDL exams in their native language. The federal rule would eliminate that flexibility nationwide.

Duffy directed the Federal Motor Carrier Safety Administration, the Transportation Department agency that oversees commercial vehicle safety regulations, to draft and enforce the new standards. Embedding the requirement in federal regulation would make it harder for future administrations to reverse.

The rule creates clear winners and losers. Segments of the trucking industry and safety advocates who have pushed for a uniform standard would get what they wanted. Drivers who relied on multilingual testing — including a large share of non-native English speakers who make up a significant portion of the trucking workforce — face new barriers to entry. Some would need language training before they can obtain or renew a CDL, adding cost and time in a sector already short on qualified drivers.

The proposal will go through a public comment period before the FMCSA issues a final rule. Once published in the Federal Register, implementation typically follows within several months.