In reply to your comment David, a caravan is nothing like a car, a caravan will totally disintergrate if it overturns at high speed. A car involved in a similar accident will be severely damaged, but will remain largely intact.
As a non dog owner, I think that all dogs should be restricted to travelling in a secure cage that is fixed to the floor pan of the vehicle. The damage that can be caused by a dog flying about unrestrained in an accident, does not bear thinking about.
Most people will have seen the stupid things that some dog owners do, IE: letting a dog sit on their lap whilst driving, having a dog sitting on the front passenger seat, or jumping about inside the passenger compartment. And the powers that be pass laws about using a mobile phone in a car, absolutely brilliant peice of legislation.
Steve W