4:16 PM PT -- Colorado State Police tell TMZ Sports that "excessive speed" is being investigated for the fatal crash of the three UW swim team members.

"The vehicle was southbound on Highway 287 and swerved to miss a vehicle in front of them stopped to make a left turn on to Larimer CR 37," CSP said.

"No alcohol or drugs suspected as casual factors."

Three members of the University of Wyoming swim team were tragically killed on Thursday after a horrific, single-car crash in northern Colorado.

According to the Colorado State Police, five passengers were traveling in a Toyota RAV4 around 2:44 PM when the vehicle swerved off the road, and rolled over, ejecting two people, and leaving the SUV mangled.

Sadly, three victims, ages ranging from 18 to 21, were pronounced dead at the scene, according to the Denver Post ... and they were members of the UW swim and diving team.

The two surviving victims are also members of the swim team.

"My thoughts and prayers are with our swimming and diving student-athletes, coaches, families and friends," UW Director of Athletics Tom Burman said in a statement.

"It is difficult to lose members of our University of Wyoming family, and we mourn the loss of these student-athletes."

The crash is under investigation ... and it is not yet known if speed, or any other factors played a role in the crash.

This isn't the first time UW Athletics has seen such devastation ... in 2001, eight runners from the track team were killed when a drunk driver crashed into their Jeep on the same highway.

R.I.P.