Typically there are more than 2 sets of tracks ~ sometimes 10, maybe 20. Depends on where and what time of day.
Last thing you want to be is a pedestrian on an Interstate.
While I don't doubt it's possible for one person to run over and kill a bicyclist who is then run over by a second vehicle, my b.s. detector is alarming because (1) the driver who claims to be the second one to run Mr. Gonzalez over did not stop and did not come up with this story right away when it would indicate someone else had killed him, (2) the driver who claims to be the second person to run the decedant over claims she only saw him in her rearview mirror (I think a person has to be Kennedy-style drunk not to see a B&B--no, Teddy, that's body and bicycle--in the road before running the B&B over, and (3) CSI had an episode in which a person was the second one to run the body over recently.
I also find your claim of up to 20 people running over the body to be--well, as incredible as a Bill&Hillary story.