Sorry to ask this weird question.
Auto insurance is bought by Parents and names Parents as insured and lists teenager as authorized driver.
God forbid, if for some reason parents die( in auto or non auto accident or other wise). Will the Auto insurance cease to exist immediately? ( Even if the premium is already paid for the policy full term)
Can the teenager still drive till the policy's expiration date ?
The exact age of the person will be important. A 16 year will likely be unable to sign the required legal documents. While a 19 year old will probably be able to sign the documents.
So if the policy included all the drivers in the household, and all the ones over 18 are deceased the coverage would lapse. If they are over 18 the policy can be reissued in the name of the teenager.
The exact state will also be important a state could set a minimum age higher than 18. All insurance in the US has an state component.
If the a family member becomes the teenagers guardian, then the teen could be added to their policy.
