The personal vehicle still is a personal vehicle with mixed use; this is not a 100% business accident. This would be like trying to state: I use it 50% for business, so two tires are business and two are personal, when I buy them. Nope. It's all part of operation and maintenance.

Keep in mind you don't deduct costs to restore an asset as if they are Operating expense. That's the main flaw I see here in your logic. You also didn't state if this is being depreciated or using Mileage Allowance for tax reporting.

The Mileage Allowance rate covers the cost of operations including maintenance and repairs.

Actual Costs would make this is an improvement, to restore the vehicle as an asset to its prior status and utility. Of course, it also depends on that total $.