How do I auto-record trips with my car's Bluetooth?

If your car doesn't have CarPlay, Bluetooth works just as well. In the Shortcuts app, create an automation: Bluetooth → choose your car's Bluetooth device → Is Connected → Run Immediately, then add Speedometer's "Start or Resume" action. Create a second automation for the same Bluetooth device → Is Disconnected → Speedometer → "Pause". This pattern works with most car stereos, motorcycle helmet intercoms, and Bluetooth GPS receivers.