While most apps will work just fine over a VPN, Android Auto isn't a traditional app. Because a wireless connection to Android Auto relies on a direct local Wi-Fi link between the phone and the car, system-level networking features like VPNs and custom proxy configurations can prevent it from connecting. Split tunneling is a common VPN feature that lets you choose which apps go through the encrypted tunnel and which ones connect directly to the internet. For Android Auto, this means the app gets the direct connection it needs while everything else hides behind encryption. Of course, split tunneling isn't just for Android Auto.