This quick answer is that there is no easy answer. Everything depends on what type of claim is being made. Car Insurance generally follows the insured for liability, uninsured motorist, and under-insured motorist claims. It usually will not be the right policy to make a property damage claim if the insured is driving a different vehicle than the one insured by the policy.
Property Damage: Property damage claims should be made with the at fault insurance party first. If the at fault party does not have insurance (or they are taking an unusually long-time determining liability), then the next best policy to make a claim through is your own insurance. You will be responsible for paying the deductible but will be reimbursed months down the line if the other insurance company accepts fault.
If you are driving a vehicle that does not belong to you that is insured, the property damage claim is best made through that policy. Your own policy likely will not pay for damages to a car that is insured through another policy. It may, however, cover any excess damages that the primary policy does not.
Bodily Injury: Bodily injury claims should be made first with the at fault party’s insurance. If there is no bodily injury insurance, then the next best policy is to make a claim is your own uninsured motorist coverage. If you are driving a vehicle that is insured by another person (i.e. your buddy’s car), the insurance policy of that vehicle will be the place to make a claim. This is because of the so-called excess coverage language in most insurance policies. This essentially says that your car insurance shall cover all claims unless you are driving a vehicle insured under a different policy. That insurance policy shall be used prior to making a claim with your own.
Uninsured & Underinsured Motorist: Each of these coverages follows the insured to whatever vehicle they are driving at the time of the accident, assuming the insured is not using the vehicle for commercial use or any other listed policy exclusion.
