The U.S. Nuclear Weapons Cost Study Project was completed in August 1998 and resulted in the book Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 edited by Stephen I. Schwartz. These project pages should be considered historical.
The Department of Energy transports nuclear weapons and weapons components via custom-made trailers known as Safeguards Transporters. Drivers are specially trained, and all shipments are accompanied by highly armed escorts. The trucks are steel-lined and fire resistant and incorporate a number of active and passive features to thwart tampering or theft.