TRIS
The Transportation Research Information Services (TRIS) database is the world's largest and most comprehensive bibliographic resource on transportation information. TRIS is produced and maintained by the Transportation Research Board at the National Academy of Sciences. TRIS contains over a half million records of published and ongoing research on all modes and disciplines in the field of transportation. Approximately 30,000 new records are added each year. TRIS is sponsored by the various State Departments of Transportation and the various administrations in the U.S. Department of Transportation.
Access is free to anyone with access to the world wide web.