What are my options in a rear-end accident if the at-fault driver's insurance refuses to cover my repair costs?
You can sue the at-fault party for negligence. Your claim is against the person who damaged your car, not their insurer, whose obligation is to their insured, not you. Your “damages” (what you sue for) would be the cost of repairs to your vehicle, plus other out-of-pocket costs you incurred due to the accident (such as car rental or towing expenses).
If the other driver’s insurer will not voluntarily offer you compensation, you can file a lawsuit against the at-fault driver for the cost to fully repair your car. If the other driver is at fault in causing the accident—and in a rear-end collision, the rear driver is legally presumed to have been at fault, since it was his or her duty to maintain a safe following distance and speed, such that he or she could stop in time. If you are within the state’s small claims threshold amounts, you can sue in small claims court on a pro se (as your own attorney) basis, to save on legal fees. (Another advantage: small claims court is faster than other courts, so you will get a resolution more quickly.)
The other option for reimbursement is to have your own insurer pay the expenses, less the collision deductible—assuming, that is that you have collision coverage on your insurance policy. Collision coverage is available regardless of who was responsible for the accident. Your own insurance company will then seek reimbursement from the at-fault driver. The advantage of submitting a claim to your own insurer is that you will get the money faster (even quicker than through small claims court), without the cost, time, and effort of a lawsuit; the disadvantage is that you will have to pay your own deductible out-of-pocket.
In addition to compensation for the repairs, you are entitled to be reimbursed for other expenses that are reasonably incurred because of the collision, such as towing charges or any rental car expenses. If your car is expensive or new (or almost new), you may be able to recover for its “diminished value,” even if it is repaired. Diminished value is the difference between the value of your car at the time of the collision and what it is worth after repair. The more serious the car damage, the greater the decrease in value will likely be. Note, however, that dismissed value claims do not apply to cars that have been totaled—i.e. when the cost to repair exceeds the then-current value of the car, in which case you receive the then-current (or “blue book”) value.
To get a fair settlement from your rear-end collision, you will need to show evidence of your claims. Showing a police report will help show the fault of the other driver, though as written above, the presumption is that the rear driver was at fault, greatly simplifying establishing fault. To prove the cost of repairs, provide accurate bills for the repairs done to your car. Also, provide receipts from any costs incurred for towing or rental cars (this also includes receipts from alternate transportation, such as from Uber, taxis, mass transit, etc.) that were paid while waiting for repair of your car. To prove that your car has lost value due to the accident, the best evidence is an appraisal performed independently by a diminished value expert, comparing the pre-accident worth of the car and what the car is worth after the repairs.