This is a question you should ask your employer, preferably before you are in a situation where you need to know the answer quickly. Some business insurance policies may cover damage or medical costs for off-duty good samaritan acts. Others may require that you submit your claim to your personal car insurer. A careful reading of your policy may help you understand its limits, but if it's confusing, don't hesitate to talk to your insurance agent so you know what to do in case of an accident.