If you are a trucker and are operating in the state of California, you are required to register with the CHP (California Highway Patrol) and obtain your CA # number.
You must then display this unique CA number on both sides of your truck in a strong bold font 2-inch lettering. Your lettering must be visible from at least 50 feet away.
Below is an example of a compliant CA & USDOT truck sign. It displays the company name, the city where they are doing business out of and their CA number.
You don’t want to give DOT or CHP any reason to pull you over.
Be compliant & display all of your information.