Guide lines which indicate the width of the vehicle (yellow) are displayed on the screen as a reference to the approximate width of the vehicle in comparison to the width of the parking space you are about to back into.
Use this display view for parking your vehicle in a parking space or garage.

a) Vehicle width guide lines (yellow)
These guide lines serve as a reference to the approximate width of the vehicle.
b) Distance guide lines.
These guide lines indicate the approximate distance to a point measured from the vehicle's rear (from the end of the bumper).
CAUTION
The guide lines on the screen are fixed lines. They are not synced to the driver's turning of the steering wheel. Always be careful and check the area to the vehicle's rear and the surrounding area directly with your eyes while backing up.
Displayable Range on the Screen
Rear View Monitor OperationMazda 6 Owners Manual: Rear Cross Traffic Alert (RCTA) (Some models)
The Rear Cross Traffic Alert (RCTA) system is designed to assist the driver in
checking the area to the rear of the vehicle on both sides while the vehicle is
reversing by alerting the driver to the presence of vehicles approaching the rear
of the vehicle.
The Rear Cross Traffic Alert (RCTA) ...
Mazda 6 Owners Manual: Locking Lug Nuts
If your vehicle has Mazda optional antitheft wheel lug nuts, one on each wheel
will lock the tires and you must use a special key to unlock them. This key will
attach to the lug wrench.
Register them with the lock manufacturer by filling out the card provided in
the glove compartment and mail ...