If it doesn't work to talk to family friends or physicians, or if these steps don't yield results, you can file an unsafe driver report with your state's Department of Motor Vehicles. (Police officers and physicians can also file unsafe driver reports.) Contact your state's DMV to find out the exact procedure, as rules vary from state to state. DMVs generally take such reports seriously, although many are too understaffed to respond quickly. Your letter should include your reasons for making the complaint, as well as information about how authorities can contact your parent or other family members. Be as specific as you can when outlining your reasons for believing that someone poses a driving risk.

After receiving a complaint, the state agency will contact the person and request a medical evaluation. The agency might also require a driving test. Depending on the findings of these evaluations, they could either restrict his license (some elderly people cannot drive on the highway or at night, for example) or revoke the license altogether.