In Utah the "rule" is 2 actions from firing to be legal OC'ing without a permit the Utah recognizes. Safeties do not count as one of the actions. Utah statute specifies for a semi-auto to be "UNLOADED" that the chamber must be empty. You are good to go with a full mag inserted into the firearm but the chamber must be empty. So the two actions would be: 1- rack slide and 2- squeeze the trigger.
For a revolver (again OC'ing without a permit) cylinder under the hammer and the next cylinder in rotation must be empty. And the two actions from firing would be 2 trigger pulls. In effect it turns a 5 shot revolver into a 3 shot revolver.
As far as car carry--- assuming you are 18 years or older, are legally able to possess a firearm, and are in legal possession or control of the vehicle, OR if you are a passenger in the car with the vehicle operators permission and you are 18 or over, and legally able to possess a firearm----
YOU CAN CARRY IN ANY MANNER YOU DESIRE-- OPEN OR CONCEALED, LOADED OR UNLOADED (referring to the firearm) or any combination of open, concealed, loaded, or unloaded.
Beware, however, the car carry applies only as long as you are in or on the vehicle (motorcycle). State gun free school zones still apply IF YOU ARE OUTSIDE THE VEHICLE. Utah's GFSZ applies to daycares, k-12 schools, COLLEGES, UNIVERSITIES, Trade schools, and UTAH's roving school zones ( either know or reasonably should have known standard applies to all the preceding.) State GFSZ is 1000 feet from the PROPERTY LINE-- NOT THE BUILDING! Utah GFSZ is more restrictive than the Federal GFSZ as the Federal one only applies to K-12 schools.
Here is a GREAT link you may find interesting as a repository of Federal and State Gun laws, Utah AG opinions, certain pertinent law cases, etc.
Generally signs in Utah restricting the possession or carry of firearms merely advise you that someone does not want you to carry there. Obviously, Post offices, Federal and state courthouses, secure portions of jails, prisons, and airports are taboo.
For areas like malls, hospitals, stores.... you can be asked to leave the premises for any reason by a person in control of the location and you could be charged with trespassing if you fail to leave upon their request. But to prevail in court on the trespassing charge against you IF you are legally at a location open to the public they must prove the you have impaired them in some way. The specifics can be found at the link posted above.