Hi, I don't trust any of the experts; They are mostly just giving their opinions. Some of them are very close and many of them are way off.
(1.) A motor vehicle which has had it's tires replaced with cheaper or skinnier tires might skid 40' longer at 60 MPH making the expert believe that the vehicles was actually going close to 80 MPH.
(2.) I did a "Power Brake Burn Out" in front of a friend's house one night. Someone called the cops. The cops saw a big pile of rubber in the street. One cop looked at the pile of rubber and said I must have been going very fast to leave that much rubber there. [actually, I only moved about three feet before the tire started spinning, doing the burn out, while I was completely stopped] [Note: this was over 50 years ago when I was a kid]
(3.) I was involved in an accident with a cop car. The cop car skidded six feet before hitting and totaling my truck. And then skidded another 96 feet. A Caprice Classic was tested to skid 135 feet at 65 MPH. In the police report they said the police car that hit me was only going 35 MPH. They either lied to protect themselves or were stupid.