This guide is for general information only and is not legal advice. Laws change — verify current rules with your state DOT or a licensed attorney before relying on this for any legal matter. Read full disclaimer.
The rule
State law allows only one earpiece at a time while cycling — covering both ears is prohibited in Maryland. See Md. Code, Transp. § 21-1126 (Headsets prohibited).
Use a single earbud and keep the other ear open to traffic. Bone-conduction headphones are a popular workaround because they leave both ear canals uncovered.