The government cares about revenue and control. It posts speed limits accordingly.
At best that is, assuming benevolent if condescending intent they are posted based on the least common denominator: The abilities (rather, the lack thereof) of the most inept Clovers possessed of a license to drive. If one old lady cant handle a curve without reducing her speed by 20 MPH or execute a safe passing maneuver without needing an entire mile of perfectly straight road to do the deed then everyone else must be compelled to operate at her level, rather than expect the old lady (and Clovers, generally) to up-rate their skills to an acceptable level.
The corollary of this dumbing-down of expectations is enforcement based not on actual harm done or even plausibly threatened bur rather on the fact of a statutory violation (as is true of 90 percent of law in this county today).
Thus people are routinely ticketed for no reason other than their having exceed an arbitrarily set and often deliberately under-posted speed limit.
Well, there is a reason: To collect revenue.
If safety were truly at issue if all these technical foul infractions were in fact dangerous then offenders would be dealt with quite appropriately criminally. The system does not ticket people who brandish firearms and then send them on their way with their weapon, on the brandishers promise never to brandish again. Yet the system as a matter of routine issues millions of tickets every single day to allegedly dangerous drivers who are in possession of an implement potentially as or more lethal than a firearm and is happy to let them continue driving, so long as they keep on paying.
It is only failure to pay that results in them deciding you must be prevented from driving. Note that even DWI offenders almost always have their driving privileges restored provided they pay the fines and pay to attend the ASAP classes and pay the insurance mafia what it demands.
So long as you pay, you are a-ok.
It is and always has been all about the money.
Well, there is one other thing: control. Deliberately under-posted speed limits (and other ridiculous traffic edicts, such as mandatory buckle up laws) provide a ready excuse for the states enforcers to pull people over almost at will. This, in turn, gives these enforcers the opportunity to look for other violations which may and often does lead to more revenue sometimes, even the vehicle itself under the war on some drugs asset forfeiture laws.
More profoundly, though, it is a way for the state, via its costumed enforcers, to assert its authority over us. To remind us As Lenin once put it who does what to whom.
It is a characteristic of unfree societies that laws and their corollary, enforcers are ubiquitous. Impossible not to encounter merely by dint of existing and trying to function.
The object is to keep people in a state of perpetual apprehension. And by people I mean ordinary everyday citizens not the always small element in any society that is actually criminal in the common law (natural law) sense of creating victims via their actions. These people the real criminals, who create real victims are incidental as far as the state is concerned. Theres no money in them. Or control, either. The sweet spot, for the coercive authoritarian state, is the average person just trying to go about his life.