The Colorado State Patrol says 57-year-old Jeffrey Detlefs of Evergreen was driving an SUV when he hit and dragged 52-year-old Rex Hegyi of Denver on the ramp from Highway 75 to eastbound Interstate 70.
Hegyi was going west on the ramp in the paved shoulder when troopers say Detlefs' Lexus hit the back of the bike, throwing Hegyi forward.
Troopers say after the crash, witnesses told them Detlefs looped back, as if to take another look at Hegyi, and then drove away.
Investigators say Detlefs had three children in his car.
Hegyi suffered serious injuries and was airlifted to Saint Anthony Central in Denver.
Investigators found the Lexus' license plate at the scene and were able to track Detlefs down and arrest him.
In addition to vehicular assault and child abuse, Detlefs also faces charges of failing to remain at the scene of an accident and driving while under the influence of alcohol or drugs.
CSP says people on bikes are allowed on the shoulder of that stretch of I-70 and a lot of them use the road.
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