A method comprising: determining, by the vehicle head unit , an authentication request for a first user; determining, by the vehicle head unit , an authentication request for a second user; in response to the authentication request for a first user, determining, by the vehicle head unit , whether a trust relationship between the first user and a second user satisfies a threshold; if the trust relationship between the first user and the second user does not satisfy the threshold, providing, by the vehicle head unit , a first authentication challenge to the first user; if the trust relationship between the first user and the second user satisfies the threshold, providing, by the vehicle head unit , a second authentication challenge to the first user, wherein the second authentication challenge is weaker than the first authentication challenge; authenticating, by the vehicle head unit , the first user using the provided authentication challenge; authenticating, by the vehicle head unit , the second user; responsive to authenticating the first user at a vehicle head unit of a vehicle, establishing, by the vehicle head unit , a session with a first user identifier, the first user identifier associated with the first user; responsive to authenticating the second user at the vehicle head unit , associating, by the vehicle head unit , a second user identifier with the session, the second user identifier associated with the second user, wherein the first and second user identifiers are concurrently associated with the session; generating, by the vehicle head unit , data while the first and second user identifiers are concurrently associated with the session; and storing, by the vehicle head unit and based on the first user identifier and the second user identifier, the data to both a first user account associated with the first user identifier and a second user account associated with the second user identifier. determining, by the vehicle head unit , an authentication request for a first user; determining, by the vehicle head unit , an authentication request for a second user; in response to the authentication request for a first user, determining, by the vehicle head unit , whether a trust relationship between the first user and a second user satisfies a threshold; if the trust relationship between the first user and the second user does not satisfy the threshold, providing, by the vehicle head unit , a first authentication challenge to the first user; if the trust relationship between the first user and the second user satisfies the threshold, providing, by the vehicle head unit , a second authentication challenge to the first user, wherein the second authentication challenge is weaker than the first authentication challenge; authenticating, by the vehicle head unit , the first user using the provided authentication challenge; authenticating, by the vehicle head unit , the second user; responsive to authenticating the first user at a vehicle head unit of a vehicle, establishing, by the vehicle head unit , a session with a first user identifier, the first user identifier associated with the first user; responsive to authenticating the second user at the vehicle head unit , associating, by the vehicle head unit , a second user identifier with the session, the second user identifier associated with the second user, wherein the first and second user identifiers are concurrently associated with the session; generating, by the vehicle head unit , data while the first and second user identifiers are concurrently associated with the session; and storing, by the vehicle head unit and based on the first user identifier and the second user identifier, the data to both a first user account associated with the first user identifier and a second user account associated with the second user identifier. <EOS>