Subaru WRX Owner's Manual page 374

When there is a downward slope
at the back
1) 3 feet (1 m)
The distance on the screen looks nearer
than the actual distance.
NOTE
When cargo is loaded, the rear view
distance on the screen looks farther
than the actual distance as in an
upward slope.
Feature of distance marker
1) 3 feet (1 m) line
2) 10 feet (3 m) line
The distance marker shows the distance
on the road. If there is a car or other object
close behind, distance cannot be correctly
displayed.
Interior equipment/Rear view camera
6-17