Neither are guns.  But you clearly are to emotionally invested in your bad argument to back down from it now.   An yes there are roads all over this state and country engineered for a safe speed double or more the posted limit.   There is one I travel on each day that is designed to be able to handle 6 lanes of traffic at 45-50 miles per hour and the speed limit was that for 20 years.   The last 7 years the posted speed limit is 30mph.   The police sit there all the time writing tickets to increase department revenue.