Can cops just pull you over for no reason?

Nope! You are wrong, driver. When you are in a commercial vehicle with a CDL in your possession, you gave up your right to say 'No" to a search of your commercial vehicle.

Had you been driving a non-commercial vehicle, then YES, you can refuse a search of the vehicle, such as your own four-wheeler, such as a car or pickup truck. For that they need Probable Cause.

 

You did not forfeit your rights simply because of your chosen occupation. The Constitution STILL applies. There are certain specific regulatory compliance items that they may check (i.e. low air light and buzzer allows them to open the door and climb up on the step to see the dash and hear the buzzer. They can also check to see that your sleeper berth has the required items...restraints, proper mattress, bedding, etc...if you've logged time in the sleeper berth.) While they are checking these items for regulatory compliance, anything you have IN PLAIN SIGHT may be used to give them probable cause to perform a more thorough search. That isn't any different than a cop looking through the back windows of your car to see if you've got anything you shouldn't laying on the back seat...and if you do and they see it, they have probable cause.

If they DON'T see anything that would give them probable cause, they still may ask for consent to search. You have the right to refuse. Commercial vehicle or not, they cannot search without either consent or probable cause...and if they had probable cause, they wouldn't be asking.