<h1>Concession models for highways: BOT, HAM and EPC determine bidding, concession terms and defect liability periods.</h1> NHAI will bid 124 highway and expressway projects across BOT, HAM and EPC procurement models; BOT and HAM projects include concession-based maintenance obligations for the concession period (generally 15-20 years for BOT and typically 15 years for HAM), while EPC contracts carry Defect Liability Periods of five years for bituminous pavement and ten years for concrete pavement.