What is the purpose of Electronic Stability Control (ESP / EBS) on modern heavy trucks and trailers?

1. Monitors vehicle yaw rate, lateral acceleration, and steering angle, automatically applying individual wheel brakes and reducing engine torque to prevent rollovers and jackknifing
2. Allows the truck to steer itself automatically without driver hands on the wheel
3. Increases maximum vehicle speed by 20 km/h in wet weather
4. Automatically adjusts the fifth wheel height while driving at 80 km/h