I have a drone programmed to follow me and post an awesome selfie video to Facebook if I crash or am hit. Last time I was hit by a car I posted a selfie video from inside the ambulance, but the framing wasn't good. I need a wider angle lens. My post-crash selfie game is weak. My friends posted better and bloodier post-crash selfies.

Semi-seriously, all the stuff other folks listed above. Most phones can be set to show emergency contact info without needing a passcode.

I carry a small wallet with just enough room for my ID, VA card, debit card and a $5/$10/$20 bill in emergency cash.