Can I start a trip by tapping the back of my iPhone?

Back Tap is a hidden iOS feature that runs a Shortcut when you tap the back of your phone — even with the screen off and the case on. First create a single-action Shortcut: open the Shortcuts app → + (in My Shortcuts, top-right) → search Speedometer → add "Start or Resume" → name it "Start Trip". Then go to Settings → Accessibility → Touch → Back Tap → Double Tap (or Triple Tap) → choose your shortcut. Now tapping the back of your phone twice starts a trip — no unlock, no app open. Perfect for cyclists, runners, and motorcyclists wearing gloves.