There are two issues which need to be adressed. First, in general, the owner of the vehicle is responsible to properly insure the vehicle. However, as a driver, you can be held accountable for not carrying enough insurance to meet your state's financial responsiblity law. Now, on a seperate issue, if you live with your mother and you drive your mother's vehicle - even once - You need to be listed on her policy as a driver. If your mother fails to list you as a driver, she runs the risk of having her insurance company deny a claim for an accident that involves you. Now, if you are not going to be listed as a driver on her policy and you are concerned about meeting your state's financial responsibility laws, you can purchase a "non owner" policy. Many insurance companies offer a "non owner policy to someone who drives occaisonally but doesn't own his/her own vehicle. A "non owner" policy typically includes liability, medical payments, and uninsured'underinsured motorist coverages. You can follow this link to learn more about your state's financial responsibility laws.