A roadside memorial in July on River Road in Bethesda at the site where three members of the Buarque de Macedo family were killed. (Dan Morse/The Washington Post)

There are the briefest of moments — just after he wakes — when the young man’s life seems normal.

Then he sees, again, where he is: jail. He quickly realizes why he landed there: speeding at 115 mph down a suburban Maryland road. And he is overcome by what he did: crashing into a car carrying a family of four to a high school play. Only one survived, a 15-year-old girl.

“I am just hoping, I am wishing, for the best way for her to be able to deal with it,” the driver, Ogulcan Atakoglu, 21, said in an interview Monday at the Montgomery County Correctional Facility.

Atakoglu has pleaded guilty to three counts of vehicular manslaughter in the devastating Feb. 27 crash in Bethesda and is scheduled to be sentenced Friday.

During the 40-minute interview, Atakoglu spoke about his previous speeding infractions and promises to himself and to courts to slow down.

“I thought I was changing myself in a lot of ways, but I never really reached the point of actually changing,” Atakoglu said.

He had felt confident that he could handle the speed of a turbocharged BMW and that, unlike those who drink and drive, he posed no danger.

“I was very naive at the time in a lot of ways,” he said. “There’s a lot of carelessness and invincibility in young people, and I think I was absolutely part of that.”

Helena Buarque de Macedo, who survived the crash on River Road, is a junior at Walt Whitman High School.

“She is doing as well as one could expect,” Principal Alan Goodwin said Wednesday. “Helena is a fine student. From the outside, she looks like a teenager who is engaged in school.”

Atakoglu faces up to 30 years in prison, 10 for each death. He will probably get less given Maryland’s history in vehicular manslaughter cases, which turn on gross negligence rather than intended harm.

Prosecutors have said they will seek a “substantial period” of incarceration for Atakoglu. They cite the tragedy of the deaths, Atakoglu’s driving record, and how fast he was going, particularly on a busy road.

“The defendant’s speed, given those factors, was extremely egregious,” Montgomery County Assistant State’s Attorney Christina Rodriguez said in court this summer.

Prosecutors also are expected to argue for a strong message of deterrence, aimed at excessive speeding.

Maryland sentencing guidelines, while not binding, call for a term ranging from several months to 12 years.

In court filings Wednesday, Atakoglu’s attorney, David Felsen, argued for a sentence of 18 months or less, noting that Atakoglu has no criminal record, took blame for the crash immediately and pleaded guilty to spare the Buarque de Macedo family from having to go through a trial.

“He never shirked his responsibility,” Felsen wrote.

The attorney also cited the “precarious” nature of the crash site at the intersection with Braeburn Parkway and noted that in August, the Maryland Department of Transportation said it would make safety enhancements that include flashing lights to warn of drivers making turns.

Friday’s sentencing before Circuit Judge Mary Beth McCormick will cover details of the crash and its aftermath.

Atakoglu was driving west on River Road just before 7 p.m. on the night of the wreck, in a car leased by his father. He was headed to his parents’ home, where he lived, in the Rockville area.

More than two football fields away, in the oncoming lanes, a Volt driven by Michael Buarque de Macedo began turning left.

In the next few seconds, police crash investigators later determined, Atakoglu flashed his lights and then applied his brakes. But for the driver of the Volt, in the dark and with headlights coming directly at him, it would have been hard to gauge the speed of the car headed toward his family.

The front of the BMW rammed the right side of the Volt.

Atakoglu got out.

“I did it! It’s all my fault!” he yelled, according to what a witness told police.

Atakoglu said he knew he was going fast but hadn’t been watching the speedometer. He was taken to a hospital with relatively minor injuries. He did not immediately know he had killed anyone. In the emergency room, a social worker told him.

Montgomery County police were already working on the two-month investigation that resulted in his charges. They calculated that if he had been going the 45-mph speed limit, he would have been 446 feet away from the Volt as it passed through the intersection.

Atakoglu pleaded guilty under a law that holds that his speed was a form of gross negligence. Prosecutors persuaded the judge to send him to jail immediately after his plea, pending sentencing. The move stunned Atakoglu, who broke into heaving sobs in court.

At the jail interview, he was more quiet but shed tears and said he fears prison time. “I couldn’t not be worried,” he said.

He tries to speak to his parents every day by phone. They also visit through a glass window and tell him to be strong even as their sorrow shows. “I’m their only child,” he said. “I never wanted to break their hearts.”

He sees a psychologist to help understand his pain but said he does not presume to know Helena Buarque de Macedo’s pain.

“I can’t even imagine,” he said. “I just pray. I constantly pray for her.”