Subaru WRX STI Owner's Manual page 388

Feature of distance marker
1) 3 feet (1 m) line
2) 6.5 feet (2 m) line
3) 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.
I n f o r ma t i o n P r o v i d e d b y :
Interior equipment/Rear view camera
6-17