Argo AI, a Ford Motor Co.-backed startup focused on driverless-car technology, laid off about 150 workers this week, a belt-tightening measure following years of fast-paced hiring.

The layoffs represented about 6% of the company’s more than 2,000-person workforce, a company spokesperson said.

“With incredible growth and progress made in our mission to deploy driverless vehicles, we are making prudent adjustments to our business plan to best continue on a path for success,” Argo said in a statement.

The spokesman added that the Pittsburgh-based startup is taking this step to correct an aggressive period of hiring and get its staffing levels back in line to hit operational goals…

As Argo has built up its business, it has lured talent from established tech companies, such as Apple Inc. and Uber Technologies Inc.

Still, the prospects of commercializing fully driverless technology remain uncertain with many executives saying the technical and regulatory hurdles are steeper than they initially envisioned.