ADAMS COUNTY, Colo. (KDVR) — A deadly crash that occurred just outside of Brighton at the intersection of 136th Avenue and Riverdale Road is now under investigation.

“The driver was kind of awake but not really responding, so I called the cops real quick,” Shawn, who pulled up just moments after the crash, said.

Shawn said he lives up the road and walks the path just east of the intersection nearly twice a day. He said Saturday morning he was heading for the first walk and saw the car in the ditch.

“It obviously hit pretty hard, they were probably speeding down the road. This spot has gotten a few people right here,” Shawn said.

Shawn called 911 and said first responders were on scene in just a few minutes. He said debris from previous deadly crashes at that intersection show just how dangerous it is. He said it’s a very dark intersection at night and a lot of people speed on this road.

”It’s a pretty deadly area right here,” Shawn said.

Several other neighbors in the area stopped to talk with the FOX31 crew on scene and mentioned similar stories of the intersection and how it’s a hotspot for deadly crashes.

According to Colorado State Patrol, when officials arrived at the scene they found the vehicle in the ditch with four occupants inside. Impairment is believed to have played a role in this accident, but they didn’t clarify if it was drugs or alcohol.

“Its based on evidence found at the scene and interactions with the driver,” Sgt. Troy Kessler with CSP said.

All three passengers, including an 18-year-old woman from Lafayette, a 23-year-old from Longmont and a 28-year-old man, were declared dead at the scene.

”Three out of four weren’t wearing seatbelts, and the only occupant wearing a seatbelt was wearing the lap portion,” Kessler said.

The driver is currently in the hospital and is in serious condition.

“There is that big double stop sign but no one is seeing that at night. They race right past it,” Shawn said.

CSP said Labor Day weekend is one of the deadliest weekends on the road for Colorado drivers.

“Make a plan, don’t get behind the wheel,” Kessler said.

CSP will have additional patrol on the road this holiday weekend.