The standards for speed limits and such are set by engineering standards.
Your general point is correct, but this detail is lacking, as it's substantially more complex. Speed limits are generally regulatory, and the road is designed with the regulatory speed in mind. Engineering judgment, backed by a speed study, can be used to set the regulatory speed, of course. The regulatory speed can also be modified by driver behaviour and politics. A few years ago, the speed limit on parts of the Rich and the Glenn was increased because of driver behaviour, even though many of the curves, both horizontal and vertical, were designed for 55 MPH.
Convince the board to change the standards, and essentially, you've changed the law.
Sort of. Many standards are set by local municipalities. Anchorage, Valdez, Fairbanks and Juneau all have different requirements for design snow loads, for example. The State has adopted the 2014 NEC for electrical design, but municipalities can modify it at need. The DOT sets the design standards for roads and highways, as allowed by statute. The board can recommend, but it's much more concerned with behaviour, ethics and competency than it is about the design standards.