The multi-lane free flow (MLFF), or barrier-less tolling system, will reduce the number of lanes required at toll plazas on newly built and under-construction national highways. Guidelines issued by the National Highway Authority of India (NHAI) have standardised the layout for highways with 4, 6 and 8 lanes.

Under the new arrangement, a 4-lane highway will have eight fee plaza lanes, including spare lanes for emergencies. Highways with 6 and 8 lanes will have 10 and 12 toll lanes respectively. Officials said the system would reduce congestion because vehicles would not need to stop to pay the user fee, removing the need for additional lanes beyond the specified numbers.

The earlier 2021 guidelines required a minimum of six toll lanes for 2-lane highways, eight for 4-lane highways and 12 for 6-lane highways. As a result, Urban Extension Road-II in Delhi, despite being a 4-lane highway, has a toll plaza with more than 20 lanes, while the 8-lane Dwarka Expressway has a 32-lane plaza built under the former boom-barrier system.

The toll lane at the payment gantry will be 3.5 metres wide to provide lateral clearance for vehicles travelling at free-flow speed and to support reliable data capture. The system will use gantry-mounted radio-frequency identification (RFID) readers, automatic number plate recognition (ANPR) cameras and related equipment to identify moving vehicles and deduct the applicable user fee through FASTag.

Vehicles without a valid and functioning FASTag will generate an electronic notice under Rule 14 of the National Highways Fee (Determination of Rates and Collection) Rules, 2008. A backup gantry will be installed beyond the payment gantry on both sides of the carriageway. Advance signs and high-mast lighting will mark and illuminate the barrier-less plaza, improving night-time safety and supporting ANPR cameras, readers and sensors.