When I was in college, I had a job working for PI's. They would investigate DUI cases leading to accidents and fatalities. This is the one case that will remain forever imprinted in my mind: A very intoxicated semi-truck driver ran over a motorcyclist on the freeway. The motorcyclist got pinned under the truck and was dragged for miles underneath with his motorcycle. The truck driver parked in his driveway with this fatally injured man still pinned underneath. The truck driver went into his house and took a shower, claiming to have been unaware of anything that happened. And yes, there were blood and flesh trails on the highway.
Never forget that case. However, I have forgotten other details over the years.
Just, to let people know, it does happen.
The PI's went to the bars this truck driver went to to interview people.
The difference here is that it happened on a fast-paced highway, where sound and sight would be muffled by the expanse of the truck and the velocity it was traveling.
Don't know if this could happen with a pickup truck and a bicyclist without being noticed.