Dear Mr. W.,
When we borrow something from a friend or neighbour, it’s common to pay for any damage that the borrowed item may sustain while in our care. That doesn’t necessarily reflect the insurance situation, though. Vehicle owners are required to have liability insurance. It covers bodily injury or damage to third-party property – like the mailbox – caused by the vehicle. In other words, the liability insurance covers the repair costs for the demolished mailbox. Payment of the car repair costs, by contrast, depends on whether your girlfriend had full or partial comprehensive cover. If she had full comprehensive cover, the insurance will pay for the damage to the vehicle, minus a deductible of at least 500 francs. If she only took out partial comprehensive cover, the policy will not cover the collision damage. She will have to pay the repair costs herself.
If you occasionally use your girlfriend’s car, I would recommend adding a “driving other cars” rider to your private liability policy. It will pay the car repair costs if your girlfriend has only partial comprehensive cover on her car instead of full comprehensive. It will also cover the deductible that your girlfriend has to pay. Finally, it also pays any premium hike that your girlfriend would owe if the accident caused her to lose a no-claims bonus.
Your private liability insurance will only cover the damage if you borrow the car occasionally, as in this case. If you use the car regularly, however, I recommend talking with the vehicle owner, i.e. your girlfriend. Together, you can work out a way for you to contribute to the costs of insuring and otherwise using the vehicle.