BOSTON (CBS) – A crash involving a school bus and a Lexus backed up traffic for miles during rush hour on Interstate 93 in Boston.

The school bus, which had no children on board, crashed just after 6 a.m. inside the O’Neill Tunnel, on the southbound side near Exit 20.

The bus came to a stop in a position that blocked all lanes inside the tunnel.

Neither driver was injured in the crash, which backed traffic up all the way to Wilmington.

State Police said the driver of the Lexus, 52-year-old Thomas Wells of Saugus, will be cited for the crash. Exact charges are not yet known.

“It was just an accident,” Wells told WBZ Thursday afternoon. “Nobody got hurt — it all happened so fast.”

Wells told other media outlets he fell asleep. But when WBZ asked him whether he was awake, he said “Of course I was. I was on my way to work like I do every day.”

Wells has a lengthy driving record. Since 1985, he’s had eight speeding violations, failed to stop for officers four times and has had two accidents.

The bus driver, 60-year-old Jean Joseph Saintine from Randolph, says he applied the brake but was worried the bus would flip over.

“I’m going straight,” Saintine says. “I was going straight and then I heard a noise. I don’t know what happened.”

In his 15 years as a school bus driver, this accident was a first for Saintine. He says, there’s only one thing that matters.

“Thank God that no kids was on the bus,” he says.

By about 7 a.m. all lanes were reopened, though residual backup was heavy.

At the time of the crash, MassDOT encouraged drivers to instead take the MBTA or seek other routes.