What is the function of Electronically Controlled Air Suspension (ECAS / Luftfederung) in heavy commercial vehicles?

1. It blows air into the cargo bay to cool refrigerated vegetables
2. It inflates the vehicle tires automatically every 5 minutes
3. It provides compressed air for the driver's beverage cooler
4. It maintains constant chassis ride height regardless of payload, allows height adjustment for loading docks (Heben/Senken), improves roll stability, and protects sensitive cargo and road infrastructure