The National Highways Authority of India (NHAI) has failed to award even a single highway development project since May this year due to economic slowdown.    This is despite the authorities taking a decision to shift to the engineering procurement contract (EPC) format for offering projects to developers, primarily to tide over the lacklustre response seen from private players to the other public-private partnership (PPP) formats that includes highway sections offered on the Build, Operate and Transfer (Toll) model.    This is the second consecutive year after 2012-13 when award of road projects has seen a dismal show. Last fiscal, awards had touched a low of 800 km. The slow pace of award is essentially because of the slowdown in the economy and the NHAI is finding it difficult to find takers for its projects, especially those offered on the PPP route.    Projects on EPC are also not coming up for bid, as they are in various stages of the project design process, NHAI said.