The Ministry of Road Transport and Highways has decided to retain the one point six four one linking factor used to convert Wholesale Price Index (WPI) data, a move set to affect the annual revision of user fees at 35 toll plazas in Karnataka. The ministry issued a memorandum on June 29 instructing that the linking factor continue to be applied when transitioning the WPI series from the 2004-05 base year to the 2011-12 series for toll calculations. The measure forms part of the ministry's guidance on methodology for national highway user fee determinations.\n\nThe decision follows observations by the Comptroller and Auditor General and directions from the Delhi High Court concerning the method used to revise user fees. Under the National Highways Fee (Determination of Rates and Collection) Rules, 2008, toll rates on national highways are revised annually from April one based on increases in the Wholesale Price Index. The rules further restrict any increase in user fee to forty per cent of the rise in the WPI.\n\nThe National Highways Authority of India (NHAI) first adopted the one point six four one linking factor in 2018 and the ministry has directed that it will apply that factor under all existing contracts and concession agreements as well as for future national highway projects. Agencies responsible for toll management will therefore continue to calculate adjustments using the same conversion methodology. Officials indicated the directive is intended to ensure consistency and legal compliance in fee revisions.\n\nThe retained linking factor means toll rates at plazas across Karnataka, including on the Bengaluru–Mysuru Access Controlled Highway and other national routes, will continue to be computed under the established approach. The move comes as several plazas have recently seen revised toll rates and is intended to provide administrative clarity. The ministry said the directive will remain in force until further orders or an amendment to the National Highways Fee Rules.