Oh boy, this is one big ole can of worms.... Yes, I remember very very clearly.
Myself along with every other handler I have spoken to regarding this do not believe under the conditions and the length of time that the dogs were tracking Amber's scent.
In terms of Lacey Peterson, sadly that dog was also raked through the coals and completely discredited. It got very ugly and was very sad for handlers all over and what we stood for. The public really didn't follow the aftermath.
Yes, special training is required for car trailing, though any dog might happen to follow one from time to time. It is still very hit and miss because variables come into play BIG TIME. The amount of time scent is going to hold on pavement, especially in the heat and weather can be greatly reduced compared to say the woods. Thus shortening the window. I could go on and on, but don't want to completely go off topic!