Car accident cases use expert opinions witnesses in several respects. An accident reconstruction expert may render an expert opinion on how the accident happened and in effect what caused the crash. The attorneys use this expert opinion to argue who is at fault. A medical doctor expert may give an opinion of several issues: namely, what injuries were caused by the collision, what treatment was reasonable and necessary for those injuries, is there a permanent injury and what future medical is needed to treat those accident related injuries. Finally, a vocational and/or economist expert may testify as to past and future loss of earning capacity. There could also be other types of experts needed depending on the specific facts of each case.
Expert opinions are necessary in most automobile accident or collision cases and workers compensation cases. It is necessary to have expert witnesses give opinions on how the accident happened and the nature and extent of the injuries. Expert witnesses usually have advanced degrees in engineering or medicine, education as well as practical work experience. Sometimes an expert witness has only work experience and may be the most persuasive. The classic example from popular culture is the female auto mechanic expert played by Marisa Tomei in My Cousin Vinny.