Explained: Technology behind India's barrier-free toll collection system

New system removes toll barriers using RFID, ANPR and LiDAR sensors, enabling vehicles to pass without stopping while laying groundwork for GNSS and V2X-based tolling

India has begun testing a new barrier-less tolling system on its highways. The government recently rolled out a Multi-Lane Free Flow (MLFF) toll plaza at the Mundka–Bakkarwala stretch on the Urban Extension Road-II (UER-II) in the National Capital Region.

 

The system, announced by the Ministry of Road Transport and Highways, removes physical barriers at toll plazas and allows vehicles to pass through without stopping. This system uses a combination of radio frequency identification (RFID) sensors and Automated Number Plate Recognition (ANPR) cameras, along with light detection and ranging (LiDAR) technology for vehicle profiling.

What is MLFF

At its core, the Multi-Lane Free Flow (MLFF) system is an electronic tolling framework that allows vehicles to be charged while moving at highway speeds, without the need to slow down or stop. Instead of toll booths and boom barriers, the system uses overhead gantries equipped with multiple technologies to detect, identify, and charge vehicles in real time. These include:

• RFID readers that scan FASTag data
• Automated Number Plate Recognition (ANPR) cameras that capture license plates
• Sensors such as LiDAR or radar to detect and classify vehicles
• Backend systems that process toll transactions instantly

In more advanced implementations, the system is also being designed to work alongside Global Navigation Satellite System (GNSS)-based tolling, where vehicles are tracked using satellite signals and charged based on distance travelled.

In the GNSS tolling architecture, vehicles equipped with on-board units (OBUs) continuously send location data, which is used for map matching, distance calculation and toll computation.

 

This creates a shift from point-based tolling (at plazas) to distance-based tolling, where users are charged for actual road usage rather than fixed checkpoints.

How the system works on Indian highways

As seen in the Mundka pilot, the system combines front and rear ANPR cameras, RFID-based FASTag detection, and LiDAR-based vehicle profiling to determine toll rates accurately.

 

RFID forms the primary identification layer, allowing a vehicle to be recognised at high speeds as it approaches the tolling zone. These systems are designed to communicate with vehicles moving at highway speeds, and simultaneously scanning the FASTag without slowing traffic.

 

ANPR cameras act as a secondary verification system. They capture high-resolution images of number plates, ensuring that vehicles without valid FASTags can still be identified and billed.

 

Vehicle classification is handled through LiDAR. These systems build a real-time profile of the vehicle’s size and shape, which is critical for determining toll categories.

 

On top of this sits edge computing infrastructure, which processes all this data in near real-time. This reduces latency and allows toll transactions to be completed in real time, without requiring vehicles to stop.

 

If the FASTag is invalid or has insufficient balance, an electronic notice is issued, giving users a limited time to pay before penalties are applied.

How is it better than existing tolling system

The shift to MLFF is largely driven by inefficiencies in the existing toll system. Even with FASTag-based electronic tolling, vehicles still need to slow down or stop, leading to congestion and delays. According to government estimates, this results in fuel wastage and increased logistics costs.

 

By removing barriers entirely, MLFF allows continuous vehicle movement. Data from early deployments shows that throughput at toll points can more than double, with over 500 vehicles passing per hour during peak times compared to around 250 in conventional systems.

 

The government also estimates that the system could save nearly 250 crore litres of fuel annually and reduce carbon emissions significantly, particularly in high-traffic regions like Delhi-NCR.

Global adoption

Barrier-less tolling is not new globally, but the way it is implemented varies significantly across regions. In parts of Europe, including Germany, tolling systems already rely on GNSS-based tracking for commercial vehicles, where onboard units calculate tolls based on distance travelled across highways.

 

The United States has adopted open-road tolling in several states, where gantry-based systems similar to MLFF use RFID transponders and cameras to charge vehicles without stopping.

 

In contrast, countries like Vietnam have deployed RFID-based MLFF systems that resemble India’s current approach, focusing on high-speed toll collection without barriers.

 

The key difference in India’s case is that it is attempting a hybrid transition. Instead of moving directly to GNSS-based tolling.

How this fits into India’s V2X plans

The barrier-less tolling system also fits into a broader push toward connected transport systems in India.

 

The country is currently exploring Vehicle-to-Everything (V2X) technology, where vehicles communicate with infrastructure, networks and other road users in real time. This includes vehicle-to-infrastructure (V2I) systems, where roads and highways interact directly with vehicles.

MLFF is effectively an early implementation of this V2I layer. It allows toll infrastructure to identify vehicles, exchange data, and process transactions without human intervention. The system already relies on continuous data exchange between roadside units, backend servers and vehicles through FASTag and sensor inputs.

 

As India moves ahead with V2X plans, including Cellular V2X (C-V2X), which enables low-latency communication over telecom networks, barrierless tolling systems could also transition from MLFF systems to satellite-enabled GNSS systems.

Challenges in scaling the technology

While the technology offers benefits, scaling it across India’s highway network comes with challenges.

 

The Ministry of Road Transport and Highways at its workshop on GNSS-based electronic toll collection system in India stated that beside infrastructural upgrades and public adoption, there are also operational concerns for scaling the technology. This also stands true for the MLFF-based tolling system that is currently being tested. These include:

• Handling vehicles with invalid or defective tracking units
• Preventing incorrect vehicle identification
• Managing lane discipline between high-speed and regular traffic
• Ensuring reliable network connectivity for real-time data transmission

The system will also need strong enforcement mechanisms, including e-notices and penalties, to prevent revenue leakage.