Car insurance laws and facts vary from state to state. The one factor that is basically the same every where is the designation of a primary and secondary driver. If two or more people are using the same address, there is need for only one insurance policy. The cost is usually based on the information of one driver, considered the primary driver. Being a secondary driver means that you drive a vehicle that is appointed to you on a regular bases. This is how the insurance has you listed, and should an accident occur while you are driving that vehicle, you are covered. The responsibility will not fall on anyone else.
As a secondary driver on someone's insurance policy, the insurance company assumes the risk of you being in an accident. Depending on the type of coverage, the primary driver on the policy will not be at fault. Because you are listed on the insurance policy, you have the same coverage as the owner of the policy. If for some unfortunate reason a law suit is filed by a victim of the accident in which you were held responsible, the suit will be against the insurance company. It is less expensive if the older person is the owner of the insurance policy since rates are determined by credit, driving history, and the age of the policy holder.
Younger people pay higher premiums if under the age of twenty five because this is considered a high risk age group. Being on an older person's insurance policy will allow you to have complete coverage with comprehensive, and many other available options. Having your own insurance will amount to half the coverage without the much needed options due to the cost. Although you are a secondary driver, you still have the same coverage that the policy provides for the primary driver. Consult your insurance carrier about rate increases after an accident.