Car B should have looked out for oncoming traffic & car A should have done the same. There needs to be a decision regarding the rate of each car’s negligence. A good example is if car A is found to be negligent by 10% & the total cost of repairs is $1000, then car A pays $100 & car B pays $900. I know I have oversimplified this somewhat. However, unless the accident had resulted – at least in part – from some foreseeable hazard on that section of the common property, it has nothing to do with the OC, except for the extent of any damage to common property. Shared driveways & roads differ from the usual traffic laws only in the speed limits.