Construction of National Highway Development Project (NHDP) could come to a halt in three months if adequate steps are not taken by the government to address problems caused by the rising prices of inputs like steel and cement, the highway builders warned. "In three months, if nothing is done National Highway Builders Federation (NHBF) will have to stop construction work,' said coordinator of NHBF V C Verma after a meeting of the federation members with PM Manmohan Singh on Tuesday.