Bedrock Robotics has raised $600 million in a funding round that values the autonomous vehicle technology startup at $4.1 billion, marking a speedy ascent for the two-year-old company.

The Series C round, co-led by CapitalG and Emergence Capital, comes two months after the startup reached a key milestone: moving its autonomous excavators beyond testing and pilot programs and putting them to work on active construction sites.

Bedrock Robotics has developed a self-driving kit that can be retrofitted onto construction and other worksite vehicles. Excavators outfitted with Bedrock’s autonomous-driving tech are now commercially operating at a Nevada-based water treatment facility, an earthwork site run by Champion Site Prep in Texas_, and a 1.2 million-cubic-yard civil sitework project with Zachry Construction Corporation.