A jury will need to answer this question in a case against a truck driver who hit and killed a trooper with the Colorado State Patrol. The fatal accident occurred back in Nov. 2016, and the criminal proceeding is just now going to trial. It will be up to a jury to decide whether prosecutors prove the truck driver's criminal negligence beyond a reasonable doubt.
Crashes that appear to involve only one vehicle at first may actually involve another vehicle. Further investigation of the scene may provide evidence of a hit-and-run. This happens in at least some of Colorado's motorcycle accidents that are blamed on rider error at first.