From what I've understood, Kevin's car going into DR's driveway and then going back out obliterated the perp's footprints and just left that solitary footprint of Jacob's digging down and resisting.
shergal, that does make sense on the surface...but....Kevin's car entering the driveway would be on the right side or nearly so....and exiting the driveway would be on the right side or nearly so...most drivers naturally stick to the right side of the road by habit + rule of the road(as compared to England)....so it appears from the photograph of Jacob's footprints that HE was in the middle of the road and assuming of course the perp had a hold of Jacob that he was either leading him(pulling him) or was alongside him. In either case, is it possible that both these sets of footprints were EXACTLY run over by Kevin's car? Imagine if you will, an adult, forcibly walking a child by the elbow(or arm).....and possibly with resistance....from the abduction site to either a vehicle or physically picking him up from the road....would those 2 sets of footprints be obliterated by Kevin's car? The physical footprints of the perp and Jacob would have had to coincide with the tire tracks of Kevin's car.