A 16-year-old Bucks County high school student was struck and killed early Wednesday by an SUV when the 18-year-old driver failed to stop for a school bus even though its stop arm was deployed and its lights were flashing, officials said.

They said the victim was crossing Bensalem Boulevard in Bensalem when the incident occurred in predawn darkness about 6:30 a.m.

"You've got two sets of lives here," said Fred Harran, the township's public-safety director. In addition to the victim, he said, the driver, who has not been charged but was being questioned, is "not going to get that out of his head."

The victim, identified as Minete Zeka, a sophomore at Bensalem High School, was treated at the scene and then taken to Aria Torresdale hospital, where she was pronounced dead, police said.

News of the accident stunned the school, said her classmates, who described her as a "positive" person. Although classes were held as usual, the day was anything but ordinary, and many students left school early after they learned what had happened.

"The school was a mess. ... Even teachers were crying," said sophomore Sadie Brennan, on her way to the accident site with two friends Wednesday afternoon to reminisce about Zeka.

She said she and her friends planned to set up some type of memorial.

Police said the school bus was stopped, with its stop arm and red signals activated, but the SUV driver didn't stop.

"Once those lights come on, the game's over," Harran said. "You need to stop."

Brennan said he was down the street at the time of the accident and saw medics trying to revive a victim. In a text message from a parent, she later found out it was Zeka. "I cried my eyes out instantly," she said.

"She was a really positive person, always nice to everyone, complimenting them and everything," said Brennan.

"She always had a way of making you feel good, even when you were upset," said Skyler Bruno, 15, also a sophomore. "She was always there for everybody."

After the accident, the SUV driver remained at the scene.

The driver had lights on top of his Ford Bronco that officials believe were for his side job plowing snow. He is "just a kid," Harran said.

The Bensalem Township School District had grief counselors and social workers available at the school all day Wednesday and will have them all week as needed, said Susan Phy, the district's school-community relations liaison.

"Our thoughts and prayers are with the family," Phy said.

In a letter Wednesday afternoon, School Superintendent David E. Baugh asked parents to discuss the "tragic accident" with their children.

A 17-year-old boy was hit and killed by a car on the same road in 2012. Ryan Viola, who was a student at Bucks County Technical School, was crossing the street to get to his bus stop when he was struck by a driver with a suspended license.

It takes only a brief period, Harran said, to stop for a school bus.

"It's a child, for crying out loud," he said. "Let the kids get across the street."