A person with comprehensive car insurance should check with her insurance provider to find out if she is fully covered while driving a vehicle owned by someone else. Some comprehensive car insurance policies include extended coverage, but a driver should never assume she is automatically covered.
Generally, a driver's personal auto insurance policy applies when an accident happens in another driver's vehicle. This coverage may have limitations. For instance, the coverage may only be applicable if permission was granted to drive the car. There are also policies that require all drivers of a vehicle be listed on the policy. Some policies are more lenient and cover any driver of a vehicle.