In a further thrust to adding more lanes to highways, the cabinet committee on economic affairs (CCEA) today approved the upgradation of existingfour-laned national highways to six lanes at a cost of Rs 5,610.77 crore.The national highways selected for upgradation include - Gurgaon-Jaipur,Surat-Dahisar, Chilkaluripet-Vijaywada and Panipat-Jalandhar. These four stretches together measure about 838 km.The CCEA decision comes afterthe public-private-partnership appraisal committee (PPPAC) of the ministry for road transport and highways recently approved five stretches for additional lanes under phase V of the National Highway Development Project (NHDP).