i think he may have been referring to the basic rule law, like the one here in oregon. the speed limit IS a guideline here and you must drive at a speed that is "reasonable and prudent with due regard to the following:

(a) The traffic.
(b) The surface and width of the highway.
(c) The hazard at intersections.
(d) Weather.
(e) Visibility.
(f) Any other conditions then existing."

how do i know this? just got a 72mph citation in a 55 zone and i'm trying to fight it in court.

this law, of course, does not cover smoky burnouts at the intersection.

and BTW, 80mph, even in a 70mph zone, is a little extreme. good luck fighting that one in court