People dont believe me when I tell them I use to drive Vegas to LA beaches in just over two hours doing 120 as much as possible. When you got into Cal and started hitting traffic it was moving at 80 - 90 in the fast lanes
I believe it. Alas, those days are long gone.
The fastest traffic flows I've seen in the US have been in Georgia. I was down there in the mid 80's for an NCAA basketball event. The Atlanta 500 finished about the same time. The slow lane was going about 90MPH. Went to a Masters event recently. Traffic flow was about the same. High end sports/luxury cars were well beyond that.