J.B. Hunt Transport Services Inc.., Uber Technologies Inc.’s freight division and FedEx Corp. are among the operators testing automated big rigs as a lack of drivers has caused ports to back up and intensified the supply-chain squeeze gripping the U.S. economy. While self-driving trucks are still years from winning regulatory approval, pioneers of the technology see it as a long-term solution to an increasingly intractable labor problem…

Labor leaders say that lawmakers need to address the impact on safety and the workforce before allowing automated trucks to be widely used.

“We would be naive to to think we could stop the technological advancement. That’s never been our goal,” said Greg Regan, president of the AFL-CIO’s Transportation Trades Department. “But we have to make sure it’s implemented in a safe way and we have to make sure that we’re also looking at the economic impact of deployment.”