Speed limits in the US have a particular problem. The speed limits are set too close to the speed people are expected to drive.

If the typical traffic speed on some highway is 65 MPH and someone is driving 76 MPH, that... isn't much different. It's not some night and day distinction where you can objectively say that 65 is perfectly safe and 76 is recklessly dangerous. The variation in stopping distance between those speeds is less than it is between one car and another from the same speed.

The normal way you resolve this sort of thing in the law is by setting a legal limit which is objectively reckless, e.g. by setting the speed limit to 125 MPH. Then you aren't actually expected to drive 124 MPH, you're still expected to drive around 65 MPH, but we can reasonably say that if you're caught doing 130 there you're deserving of some penalties.

However, that doesn't generate fine revenue because then hardly anyone actually drives that fast. What generates fine revenue is setting the speed limit there to 55 MPH even while the median traffic speed is still 65 MPH, and then doing only enough enforcement to make sure people don't follow the law. You maximize revenue when everyone is "speeding" all the time and all you have to do is post a patrol car there once in a while and rake in the dough. But that also makes it unjust to impose harsh penalties for it because then receiving a citation is a matter of bad luck rather than doing something outside the bounds of reasonable and expected behavior.