What is the function of the Automatic Traction Control (ASR / Antriebsschlupfregelung) in a heavy commercial vehicle?

1. It automatically turns off the truck headlights in rain
2. It deploys mechanical snow chains while driving at 80 km/h
3. It changes automatic transmission oil every 100 km
4. It prevents the drive wheels from spinning uncontrollably during acceleration on slippery surfaces by selectively applying wheel brakes and reducing engine torque