This type of coverage is getting more important all the time. Medical payments coverage (it is often referred to as "medpay" in the legal world) is a small health insurance policy that will promptly pay a portion of your medical bills including co-pays and deductibles if you have been in an accident.
Remember that the person who caused the accident will ultimately be responsible for your medical bills, but that claim could take years and having medical payments coverage even if you have a health insurance policy is something that is generally worthwhile.