Are witnesses necessary in a Tennessee 18-wheeler accident case?

It is not absolutely necessary that you have witnesses to proceed with an accident case against a trucking company. If there are witnesses and the police who investigated the accident are able to identify them, they'll be on the police report. Whether or not there are witnesses, you will still be able to proceed with your case relying upon your own explanation of how the accident happened, the explanation of any passengers in your car and the expert testimony of an accident reconstructionist which an attorney experienced in handling trucking cases will hire to testify on your behalf.