Llano Road in Sonoma County is a narrow road that sharply slopes downward and has a reputation where people speed.
Graduation is three weeks away, but at Rancho Cotate High School there is only sadness instead.
"I've never lost anyone, ever and this is horrible. I don't know how to deal with it," said Cheyenne Williamsen, a friend of Carlson's.
Williamsen sent ABC7 News a photo from Wednesday that quite possibly may have been the last ever taken of the 17-year-old.
A few hours later, at a spot along Sonoma County's Llano Road, she would lose her life between a tree and utility pole.
"She was getting to a point in her life where she was so happy and so content with everything and it got taken away from her. It's not fair," said Williamsen.
In Sonoma County, Llano Road has a reputation for being narrow, skinny, and rough.
Wednesday night, Carlson was a passenger in a car with two friends when the driver, 18-year-old Ashley Kellogg, hit a pothole and lost control. Two were left injured and one dead in the accident. The California Highway Patrol suspects speeding.
"The speed limit is 45. But it is a rural, country road, very bumpy, so 55 would be pushing it," said CHP Officer Jonathan Sloat.
The timing could not have been more cruel -- just last weekend, Carlson celebrated her senior prom, and had worked hard to graduate. She was popular and quiet, her friends say.
"She was an outstanding person. She was so beautiful just inside and out. She lit up the room, always," said Williamsen.
When asked when the last time was that she saw Carlson, friend Megan Dodson said, "Yesterday in class. She was just sitting there, like normal. Just happy and today she's just gone."
At Rancho Cotate High School, it's an experience not on any curriculum, that life is precious. It's a lesson learned the hard way in senior year.