Why should part of the vehicle be visible in a properly adjusted side mirror? Question Why should part of the vehicle be visible in a properly adjusted side mirror? Answers It limits the view behind the trailer. It provides a point of reference for the driver. It allows the driver to see stickers placed on the side of the trailer. Explanation Side mirrors should be adjusted to display part of your vehicle. This will provide a point of reference when judging the location of nearby objects. This questions appears in the following tests: Connecticut Class B Knowledge Test Mississippi Passenger New Mexico Class B Knowledge Test Oklahoma Class A Knowledge Test Virginia Passenger