people not following the 'rules' are the instigators of change.
Change can be for the good of society, but it can also have a negative impact. Standardization of rules for communication is a good thing. Ignoring the standardized rules degrades the quality of the communication.
Frankly, if most drivers ignore a speed limit and there's no significant increase in accidents, to me that indicates it was a bad speed limit in the first place.
You and I both know that I am talking about people exceeding the legal speed limit at a given location. The actual legal speed at a given location can be higher or lower than it is at another location. How the legal speed at a location is determined is up to the local authority. Regardless of whether the legal speed is lower than it needs to be, the proper way to change that value is community action.
Considering the poor driving skills exhibited by many drivers, any increase in a legal speed limit will most likely result in an increase in the number of accidents. If you set the limit at 30, they will do 40, and if the limit is changed to 40, they will do 50, etc. The severity of the higher-speed accidents will also be higher due to the higher impact forces. That means an increase in the number of injuries, more people requiring hospitalization, and a higher death rate.