(including but not limited to)
U.S. Federal Court, Virginia- Tennessee

Commonwealth of Virginia, General Assemby- Expert Testimony Concerning Virginia State Code and Stopping Distances

Commonwealth of Virginia, General Assemby- Expert Testimony Senate Sub-Committee on Trransportation

Harrison County, Mississippi Circuit Court

Rockingham County, North Carolina Superior Court

Pittsburgh City, Pennsylvania Circuit Court

Court of Common Pleas of Schuylkill County, Pennsylvania

Allegheny County, Pennsylvania Circuit Court

Dickson County, Tennessee Circuit Court

Wilson County, Tennessee Circuit Court

Danville County, Virginia Circuit Court

Richmond City, Virginia Circuit Court

Chesterfield County, Virginia Circuit Court

Alexandria City, Virginia Circuit Court

Woodstock City, Virginia General District Court

Portsmouth City, Virginia General District Court

Newport News City, Virginia General District Court

Buchanan County, Virginia Circuit Court

Fairfax County, Virginia Circuit Court

Gate City, Virginia Circuit Court

Goochland County, Virginia Circuit Court

Louisa County, Virginia Circuit Court

Norfolk City, Virginia Circuit Court

Spottsylvania County, Virginia Circuit Court

Stafford County, Virginia Circuit Court

Staunton County, Virginia Circuit Court

Virginia Beach City, Virginia Circuit Court

Gloucester County, Virginia Circuit Court

Greene County, Virginia Circuit Court

Newport News, Virginia Circuit Court

Amelia County, Virginia Circuit Court

Richmond City, Virginia Juvenile Court

Admissibility in most states is governed by Evidence Code and case law.
If a witness is testifying as an expert, his testimony in the form of an opinion is limited to such opinion as: a subject that is sufficiently beyond common experience that such opinion would assist the trier of fact; and is based on matter (including his special knowledge, skill, experience, training and education).
For expert opinion testimony, to be admissable:
The subject matter must be "sufficiently beyond common experience" that the opinion would assist the jury;
The witness must have appropriate qualifications, i.e., some special knowledge, training, or experience in that subject matter; and
The opinion must be based on reliable matter.
Federal ("Daubert"): whether expert opinion testimony is valid and hence, relaible, may be measured by the following factors:
Whether the theory or technique can be and has been tested? That is, can the theory or technique be tested empirically?
Whether the theory or technique has been subjected to peer review and publication?
Whether in respect to a particular technique, there is a high "known or potential rate of error" and whether there are "standards controlling the technique's operation"? That is, is the error rate acceptable?
Whether the theory or technique has achieved general acceptance within the relevant scientific community.
Whether the expert is proposing to testify about a matter growing naturally and directly out of research he/she has conducted independent of the litigation, or whether he developed his opinions expressly for purposes of testifying.