Uber wants to recruit teachers with free time on their hands during summer vacation to become drivers for the rapidly expanding ride-sharing service.

To sweeten the deal, the company will offer a $250 bonus to any teacher who signs up to drive by June 30 and completes 10 trips. Any current Uber driver who refers a teacher who meets this threshold will also receive $250 from Uber.

“Teachers are committed, service-oriented people who are making a difference every day, so they’re ideal partners,” said Uber spokeswoman Brooke Anderson. “As summer arrives, driving with Uber is another opportunity to improve the Chicago community by providing safe rides. We’d love to have more educators on board.”

To qualify, teachers must send in a photo of their teaching certificate.

There are more than 15,000 Uber drivers in Chicago. Uber classifies them not as employees, but as independent contractors.

In the last year, Uber has announced various similar initiatives to expand their driver pool, including a commitment to hire 1 million women by 2020 and 50,000 veterans by March 2016.