Mazda CX-3 Owner's Manual page 286

When Driving
i-ACTIVSENSE
How to Set the Distance Between Vehicles During Headway Control
The distance between vehicles is set to a shorter distance each time the
The distance between vehicles is set to a longer distance by pressing the
distance-between-vehicles can be set to 4 levels; Long, medium, short, and extremely short
distance.
Distance-between-vehicles guideline
(at 80 km/h (50 mph) vehicle speed)
Long (about 50 m (164 ft))
Medium (about 40 m (131 ft))
Short (about 30 m (98 ft))
Extremely short (about 25 m (82 ft))
NOTE
The distance between vehicles differs depending on the vehicle speed, and the slower
   
the vehicle speed, the shorter the distance.
When the ignition is switched to ACC or OFF and then the engine is started again, the
   
system automatically sets the distance between vehicles to the previous setting.
4–148
switch is pressed.
switch. The
Display