The rest of your statements are pretty well founded but > There is not a hard law that states speed limit at least in California Incorrect. I don't know what

The rest of your statements are pretty well founded but > There is not a hard law that states speed limit at least in California Incorrect. I don't know what you mean by "a hard law", but, in California, there is a section, from the very statues you present, that sets a statutory maximum limit. The complication, being that there are three maximum speed limits in California: 55mph, 65mph and 70mph, depending on the scenario. CVC §22349 sets a maximum speed limit of 65 mph throughout the state (except for the 70 mph limit on some freeways). CVC§22349(a) reads: Except as provided in Section 22356 [70 mph on some freeways], no person shall drive a vehicle upon a highway at a speed greater than 65 miles per hour. The CVC§ 22356 referred to above allows a 70 mph speed limit if justified by an engineering and traffic survey where a 65 mph limit would otherwise be applicable. Try arguing the 22350 while you have been cited the §22349 on a ticket. Not going to fly regardless of what one might read on websites online.