Can you total a car at 10 MPH?

It would depend on the car, what damage it sustains and how much it will cost to fix, compared to how much the car is worth. For example, in the early 90's, brand new Chevy Sprints, still on the dealer's car lot, would be considered totalled if the windshields were broken by vandals. This was because it actually cost more to replace the windshield, than it did to replace the entire car.

Note for Britons: 'To total' in the USA means 'to write off' in the UK.