I suppose you also grant the "company" the right to forbid CB radios in your car, forbid CD players in your car, forbid V8 engines in your car ad infinitum ad nauseum?
You may not need a weapon at work but between home and work is the hazard for many and the right of firearms possession is not based upon need. I work for the U.S. Government and am prohibited from bringing a firearm or other weapons to work in my automobile. If we bring needs into the question, I have never needed a firearm between home an work but nearly needed one at work a few years ago when a disgruntled worker started killing others on the job.
I will agree with the company about weapons outside of the vehicle but inside the vehicle, it is none of their business.
Then park at the curb....
NeverGore :^)
An employer can pass such rules. You're free to quit and work elsewhere if your employer is a jackass.