I think it's how far away is the obstruction before you get a warning. Think about it this way, near = delayed warning. The object will be close to you before it beeps and the car slams on the brakes automatically. Far means the obstruction will be far away and the car will beep giving you more reaction time to brake on your own. I keep mine at far after a few incidents where the car would beep and slam the brakes almost simultaneously. Now it's a bit better, though I've had times where it just slams on the brakes like half a second after.