“We have enough wireless to make your fillings hurt,” says Matt Federoff, the district’s chief information officer.

District officials got the idea for wiring the bus during occasional drives on school business to Phoenix, two hours each way, when they realized that if they doubled up, one person could drive and the other could work using a laptop and a wireless card. They wondered if Internet access on a school bus would increase students’ academic productivity, too.

Image On buses equipped with Wi-Fi in Vail, Ariz., officials say more homework is getting done, and there's less rowdy behavior. Credit... Joshua Lott for The New York Times

But the idea for the Internet Bus really took shape in the fall, when Mr. Federoff was at home, baby on his lap, and saw an advertisement in an electronics catalog offering a “Wi-Fi hotspot in your car.”

“I thought, what if you could put that in a bus?” he said. The router cost $200, and came with a $60 a month Internet service contract. An early test came in December, when bus No. 92 carried the boys’ varsity soccer team to a tournament nearly four hours away. The ride began at 4 a.m., so many players and coaches slept en route. But between games, with the bus in a parking lot adjacent to the soccer field, players and coaches sat with laptops, fielding e-mail messages and doing homework  basically turning the bus into a Wi-Fi cafe, said Cody Bingham, the bus driver for the trip.

Mariah Nunes, a sophomore who is a team manager, said she researched an essay on bicycle safety.

“I used my laptop for pretty much the whole ride,” Mariah said. “It was quieter than it normally would have been. Everybody was pumped about the games, and there were some rowdy boys. But the coach said, ‘Let’s all be quiet and do some homework.’ And it wasn’t too different from study hall.”

Ms. Bingham recalled, “That was the quietest ride I’ve ever had with high schoolers.”

Since then, district officials have been delighted to see the amount of homework getting done, morning and evening, as Mr. Johnson picks up and drops off students along the highway that climbs from Vail through the Santa Rita mountains to Sonoita. The drive takes about 70 minutes each way.