If i was driving my friend's car and got hit-and-run (other car not found), who is responsible for damage?

Unless you told your friend you would pay any damage to the car even if somene else is responsible then the hit and run driver (who I assume was 100% at fault) would be the one responsible for the damage. If that person is not found then your friend suffers the loss of his car. You would not be responsible if the accident was 100% the fault of the hit and run driver. Your friend assumed the risk of the damage to his car by uninsured and hit and run drivers since he did not purchase collision coverage.

In my answer I am assuming the accident was the hit-and-run driver's fault, and that he wasn't caught. The way auto insurance works is this: insurance "follows the car." That means that when several polocies are potentially on the risk, the first place you would look for coverage is your friend's auto policy under the collision coverage, since that policy pertains specifically to the car involved in the accident. It your friend does not have collision coverage, then your policy is the next place you would look, since you were permissively driving the car, and your insurance follows you into cars you are permissively using, such as rentals or borrowed cars. So call your friend's carrier first, then yours. Good luck.

Hmmm....could involve the law of bailment. If you borrowed your friend's car for your own purposes, then friend could argue that he "bailed" the car to you, such that you could be on the hook for the damage. Would need more facts to evaluate your case properly, as there are different types of bailment -- e.g., gratuitous, bailment for hire, etc. -- and a different standard of care (reasonable care, extraordinary care, etc.) applies depending on the type of bailment involved. Best bet: if somebody is asking you for money on account of the collision, talk to an attorney -- sooner, rather than later. Regards... E. Ryanen, atty