Actually, being serious for once, I have been in this situation myself earlier in the year.
I got knocked off my bike cycling home from work one evening and as a result suffered a broken neck, fractured skull and was knocked unconscious. By all accounts I came around pretty quickly and even got up! I have no recollection of this or the next 20-30 minutes but apparently despite being a bit dazed (unsurprisingly!) I was pretty good at giving the emergency services my name, wife's name, home phone number and address. It was about 15 minutes after my expected arrival time and my wife was just starting to worry when she got the call. It still nearly brings me to tears to type this 3 months later, when I think about her getting that call and what it could have been if things had been worse!
Anyway, back on topic. If I hadn't been able to give details myself I do have a few back up methods that should be enough to identify me, even if it takes a bit of detective work by the police to do so.
- My work pass card has company name with my name and picture. I will always have this with me when travelling to/from work.
- My phone doesn't have an ICE contact saved but it doesn't need a PIN to access it so simply dialling HOME (we all save our own landline number as HOME don't we?) or one of the recent/frequently dialled numbers should get through to someone that will know who the phone belongs to. If not then the SIM card is registered to my name so that can also be used, even if the phone is broken.
- My cycling keys (the key to get into the house through the bike shed door & keys for bike locks) also has a tough metal USB memory stick attached. On this is a Notepad document that has my name, email and mobile number (No address as keeping my address with the house key would be plain stupid!). Should I lose it and the keys I might hopefully get them back. I have just added my wife's mobile number as an ICE contact, but not the home phone number because Googling that brings up my address).
- My Garmin only gets used for bigger leisure rides so I don't often have it with me when cycling, but just in case of theft it also has a Notepad document similar to my USB. If the police connected the Garmin to a computer and browsed the files they would see one called OWNER and this does include name address and other contact details to help it get back to me should it be lost or stolen/recovered. I have also recently edited the start-up screen to include my contact info as covered in THIS THREAD.
- I may have my bank cards with me, but again not always. I usually do take one if going for a bigger ride, just in case.
I don't make sure to have all or any of these each time I go riding so could actually end up like the individual in the case that has prompted this thread. I don't have an I.D form that I carry each time but rely on the probability that at least one of the above will allow me to be identified and next of kin informed should the worst ever happen.