In California, it's a real pain, if not impossible to return a vehicle to the road after being salvaged.
Found this out the hard way when my daughters car was "totaled" in a rear end accident. It was a 20 year old Honda Civic I bought for $800 at an auction. Spent some cash fixing it up and put a paint job on it so had about $2K into it, about what KBB said it was worth. Great car, great mileage.
About a year later she was rear ended. The trunk was munched but everything else was okay. I bought it back from the insurance co then went into DMV hell trying to get all the inspections and jump through their hoops. that was even before I tried spending any money on the bodywork. Gave up, I couldn't take the bureaucracy anymore so drove it over to pick a part and dropped it off. Luckily they gave me what I spent to get the car from the insurance company.