The sky-blue Divvy bikes that descended on Chicago in the summer of 2013 have become a key part of the city’s public transit system.

And no one knows Divvy better than Elliot Greenberger. The 35-year-old Lincoln Park resident has been at the helm of West Town-based Divvy since he came there from Groupon in April 2013. He helped launch the system on June 28, 2013.

At Divvy, Greenberger has held the titles of director of marketing, deputy general manager and, most recently, general manager. Now, he’s leaving Divvy at the end of the year to join Lyft, where he will oversee marketing and operations for Orange County, California, and other areas surrounding Los Angeles.

“Launching and leading Divvy for the past four and a half years has been such an incredible experience,” Greenberger announced online. “Truly have had the best and most challenging months of my professional life, but there’s never been a day I didn’t have fun making our mark on Chicago.”

The bike-share program is operated by Motivate in partnership with the Chicago Department of Transportation. Divvy riders pay for yearly memberships or rent bikes by the day. Altogether, they have taken more than 13.6 million trips and peddled 27.8 million miles.

Divvy hasn’t named Greenberger’s successor.

Greenberger spoke with the Chicago Sun-Times about his time at the city’s first bike-sharing system, which employs between 70 and 130 workers who maintain a fleet of more than 6,000 bikes at 582 docking stations.

Question: What have been some of the biggest successes, pleasant surprises and unexpected challenges from operating Divvy?

Answer: I’ve loved watching how our riders have taken to the system and hearing all the ways they use Divvy to get around. It’s been surprising just how much of a positive impact Divvy has had in our riders’ lives. It was amazing when we passed the 10 million trip mark earlier this year. But what’s even more amazing is thinking about what those trips have made possible in people’s lives.

It’s not easy rolling out a new transportation system across the city. We’ve run into any number of challenges, from operating through two back-to-back polar vortices in winter 2014 to supply-chain issues. Our goal has always been to serve our riders so well that they don’t even think about all the work that goes on behind the scenes.

That said, we launched Divvy at an opportune time, when the mayor was leading the push to add more than 100 miles of protected bike lanes throughout the city. That definitely helped set the stage for Divvy’s growth in the first few years.

One of my favorite stories is from a family that was visiting Chicago for the weekend. When they got home, the daughter painted a picture of their family trip. In that painting, the family was standing next to a Divvy bike with the famous Chicago skyline reflected in the Bean behind them. They had used Divvy to get around that weekend. My hope is that Divvy is part of the fabric of the city in the same way the Bean is and that it continues to be a meaningful part of how people experience Chicago.

A Divvy bike station at Daley Plaza

The first Divvy bike station was at Daley Center Plaza. | Alisa Hauser / Sun-Times

Q: Did you expect Chicago to embrace Divvy as enthusiastically as it did?

A: When I joined the launch team in April 2013, there was no such thing as “Divvy.” The job description was for “Chicago bike share.” I hadn’t seen bike share in the states at that time, and I remember thinking, “This is either going to be a very small, precious program, or it’s going to be something big and transformational.”

I knew we were onto something when Divvy immediately became a verb and when people dressed as Divvy bikes for that first Halloween. I think the fact that it took off as it did speaks to Chicagoans’ readiness for innovation.

Q: How often are Divvy bikes lost or stolen and result in a $1,200 fine?

A: Chicagoans have treated these bikes very well. Because they’re heavy — 43 pounds — they’re easily identifiable, and many of the components are proprietary. You don’t have a huge incentive to keep it as your own. For those reasons, over 90 percent of bikes that go missing have come back.

Q: What is your favorite Divvy station — and why?

A: I’ll always have a soft spot for the Divvy station at Daley Center Plaza because it was the first station we deployed back in 2013. That station is still there today, although it has moved to various corners of the plaza over the years. It’s one of our busiest destination stations on weekday mornings.