Where does the acceleration lane begin?

If it was me that the officer clocked for speeding, it was on a stretch of road I consider to be an acceleration lane approaching the freeway, and should therefore be considered a 65 zone instead of a 50. This road parallels the freeway for a while before actually connecting. At what point does a road officially become an acceleration lane to the freeway?
--Mickeymouse in Salt Lake City, Utah * Home of the 2002 Winter Olympic Games

Where the ramp begins is not exactly a cut and dry case since every interchange is different, but typically once you pass the gore nose that seperates the frontage road from the ramp entrance would be considered the beginning of the ramp us thus vehicles could accelerate to highway speeds.
Sounds like you were clocked while still on the frontage road, but hard to determine without seeing diagrams, jurisdiction limits, and official speed zones.