WARREN, Mich.—A boy grabbed the steering wheel on a school bus and hit the brakes, bringing the vehicle to a safe stop on a busy Detroit-area road after the driver had passed out, authorities said.

“Someone call 911. Now!” seventh-grader Dillon Reeves shouted to dozens of other middle-school kids on the bus Wednesday.

Dillon was hailed as a hero: He stopped the bus as it was veering toward oncoming traffic.

“In my 35-plus years of education, this was an extraordinary act of courage and maturity on his part,” said Robert Livernois, superintendent of Warren Consolidated Schools.

The incident was recorded on a video camera just above the driver. The video shows the driver fanning herself with a baseball cap and informing the transportation office that she needs to pull over.

Seconds later, Dillon jumped into action, hitting the brake pedal and clutching the steering wheel.

“I don’t know that it could have gone any better,” Livernois said, noting that adults helped children out the back door. “When you have an anchor like Dillon taking care of business on the bus, it really and truly was a good day for us.”

Dillon declined to speak to reporters Thursday, but his parents, Steve and Ireta Reeves, were proud.

“We’ve got a little hero,” Dillon’s dad said. “He’s been on my lap driving country roads, pulling into driveways since about 4 years old … He’s a good driver.”