After five and a half years running Waymo, Alphabet’s subsidiary developing autonomous drive technology, John Krafcik decided it was time for someone else to run the company. In fact, two top Waymo executives, Tekedra Mawakana and Dmitri Dolgov, will become co-CEOs of the company.

In a blog post explaining his decision to step down as CEO but continue to act as a consultant to Waymo, Krafcik wrote, “Now with the fully autonomous Waymo One hail service, open to everyone in our Metro Phoenix launch area , and with the fifth generation Waymo driver prepared for use in hailstorm and goods delivery, it is a wonderful opportunity for me to pass the baton as Co-CEOs to Tekedra and Dmitri. ”

Tekedra Mawakana is moving to the top position four years after joining Waymo and was most recently Chief Operating Officer. Dmitri Dolgov started his career at Waymo in 2009 when the company was founded and known as the Google Self-Driving Car Project. He becomes Co-CEO after most recently as Waymo’s Chief Technology Officer.

In a joint statement to Waymo employees, Mawakana and Dolgov wrote, “We are determined to work with you to develop, deploy and commercialize the Waymo Driver and drive the success of our incredible team and this road and opportunity ahead of us.”

While Waymo has established itself as a leading developer of autonomous vehicle technology with more than 32 million kilometers driven on public roads and more than 32 billion kilometers driven in simulation, the company’s conservative approach to expanding operations has frustrated those who rely on Self-drivers hope vehicles across the country. This deliberate approach was central to Krafcik’s tenure as CEO.

In meeting with reporters, Krafcik regularly stressed the importance of Waymo’s autonomous vehicles being as safe as possible. In March 2018 after a pedestrian was hit and killed by an autonomous Uber vehicle that was tested on a public road in Arizona, Krafcik told CNBC, “Part of our responsibility at Waymo is to help the world and cities in that we act to secure and the regulators that regulate these cities understand our technology. ”

Waymo One autonomous hail service has been offering rides in the Phoenix region since 2017. It has evolved from a pilot program with a limited number of pre-selected customers to a publicly accessible hail service that uses a fleet of vehicles that drive without a driver. While Waymo has discussed expanding the Waymo One Autonomous Public Use Program to other cities for public use, the company has not come up with a final plan for it.

In the meantime, Waymo Via, which is designed for the autonomous transport of goods, is being tested with truck hubs in Arizona and Texas. At the end of last year, Waymo and Daimler’s Freightliner signed a contract to develop fully autonomous trucks.

– CNBC’s Meghan Reeder contributed to this article.