"TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 455: Alternative Technical Concepts for Contract Delivery Methods Transportation documents various methods by which agencies have successfully implemented alternative technical concepts (ATCs) during the highway contracting process. The report identifies methods that promote transparency and fairness, while at the same time protecting the industry's right to confidentiality. The U.S. Federal Highway Administration defines an ATC as "a request by a proposer to modify a contract requirement, specifically for that proposer's use in gaining competitive benefit during the bidding or proposal process ... [and] must provide a solution that is equal to or better than the owner's base design requirements in the invitation for bid or request for proposal document."--Publisher's note.