I'm a Type 2 diabetic, an asthmatic and I also have some medication allergies. I always carry ID in about 3-4 places when I ride. I carry a couple of business cards in my underseat equipment bag (where I also carry an extra asthma inhaler, tire tools, lock, plastic bag to keep my seat dry in the rain, etc.). I have my name written on the back of my helmet, I usually carry a wallet with ID, and I wear a Medic Alert necklace that looks like a black dogtag. The Medic Alert system keeps your medical information on file, so EMS personnel can call an 800-number for any health issues they should know about, your contact information, etc. I work for a tribal health care organization that has its own hospital, so I've seen some of the emergency cases and know to have ID at all times. Medic Alert now has those keychain computer drives so you can transport your electronic health records with you. http://www.medicalert.org