From Drivers Manual...
"Passing Speed Limit Exception: If you are driving a passenger vehicle, motorcycle or pickup, not towing another vehicle, you may exceed the posted speed limit by up to 15 miles per hour, while passing another vehicle that is traveling below the posted speed limit on a two lane roadway. The posted speed limit must be 55 miles per hour or greater. This does not apply in work zones. You must return to the right-hand lane and reduce speed to the posted speed limit as soon as practicable."
Basically you may pass going up to 15 mph over the speed limit IF...
1. You are driving a vehicle without a trailer and
2. The vehicle you are passing is going under the speed limit and
3. The posted speed limit must be at least 55 mph and
4. You are not in a construction/work zone.
So this includes Hwy 16, 21, 55, and 95