TrafficInfraTech Magazine Linking People Places & Progress
Rajesh Krishnan, Director, ITS Planners & Engineers Pvt Ltd
Toll payments on National Highways have moved digital with the introduction of FASTag. However, we still see sizeable queues during peak hours at some of the busy toll plazas. Hence, the government is exploring mechanisms that will reduce the delay at toll plazas even further. Rajesh Krishnan, Director, ITS Planners & Engineers Pvt Ltd explains about two such technologies – GPS based tolling and ANPR based tolling.
GPS-based tolling involves installation of black boxes on all vehicles. It is an active device that will draw power from the vehicle battery and calculate the applicable toll for vehicle journeys in conjunction with a tolling server based on vehicle locations. The system design can vary based on the level of trade-off between local data processing and bandwidth requirements. At the one extreme, the devices can simply notify the server their locations at a fixed time interval. The server will have the onus of matching the locations against road sections where toll charges are applicable and calculate toll fees.
This model will not only incur a high data transfer cost but also would require more computing capacity for the servers. At the other end of the spectrum, the device can store a local cache of the road network with tolling and the rules for calculating the toll charges. For example, geo-fences could be defined at the locations of existing toll plazas and vehicles travelling through those geo-fences could be charged a toll fee that is currently levied at those plazas. The device would communicate the toll amount to the server that will carry out the financial reconciliation. This architecture would require the use of black boxes with non-trivial processing power. This would increase the cost of devices, and would draw ire from citizens if the cost is passed on to them. A potential alternative is a secure mobile application (along the lines of DigiLocker) published by the government, which will have the advantage of a smaller server infrastructure and no cost to the public.
While such a GPS based system solves the issue of queue elimination at toll plazas, there is no element of monitoring or enforcement. It would be easy to avoid toll fees by simply disconnecting the power cable to the black box. In order to address this issue, one needs an independent technology based monitoring and enforcement sub-system such as a gantry mounted Automatic Number Plate Recognition (ANPR) cameras backed module that records all the vehicles travelling through specific points on the road. (As an aside, one needs to also consider the scenario where the black boxes are faulty. Such cases are not instances of willful tampering and no penalty should be levied).
An enforcement sub-system would detect all the vehicles travelling through a particular point on the road network. This dataset can be compared against the GPS based tolling data and vehicles that are identified to have travelled past a tolling point without a functional black box can be penalised. The enforcement sub-module can also make use of RFID in addition to ANPR to take advantage of the current FASTag penetration so that the number of undetected vehicles can be minimised. This raises the question of why we need a GPS black box in the first place if all vehicles are detected by the enforcement sub-system considering the humongous logistics involved.
Different road authorities have tried to find a satisfactory answer to this question given their own unique context. For example, Transport for London (TfL) decided not to use GPS, even though the GPS accuracy in central London was found to be satisfactory given that an enforcement sub-system is required anyway. Some European countries, on the other hand, decided to go with black boxes. This is due to another question that needs to be considered when contemplating tolling technology upgrade: what is the current road pricing mechanism and is it likely to change?
Congestion charging is levied iwwn London if vehicles use city centre roads during business hours; a cordon of ANPR cameras monitor all entry and exit points to the congestion charging zone. Congestion charge is deemed applicable to a vehicle if it is found entering or leaving the congestion charging area during relevant hours. Hence, it is essentially a location based charging mechanism that is not too dissimilar to the tolling scheme currently used in India.
ANPR does not capture all the vehicles even with advances in technology. Hence, the London scheme requires all vehicles entering the congestion charging area to pre-pay or make payment within a specific time interval of using the central London road network. Vehicles that are detected by ANPR cameras but not paid the congestion charging fee are fined. This encourages travellers to voluntarily make payments to avoid being fined. One could argue that a similar logic could be applied in the Indian context and a combination of ANPR and RFID readers at existing toll plaza locations acting as an enforcement sub-system is the simplest solution to avoid queues at toll plazas.
But this will result in the nation committing to the continuation of the existing toll pricing mechanism. European countries that have adopted distance-based pricing decided to adopt the black boxes in vehicles approach backed by a camera based enforcement sub-system. This results in a fairer toll fee for the public as the fee paid is in proportion to the distance travelled on the highway. However, existing contracts with concessionaires are based on toll fees levied at specific points on the highway. Changing the toll pricing scheme would involve changes to existing legal contracts that could turn out to be a complex undertaking.
Ultimately, this would be a policy decision and the choice of technology would depend on the policy adopted. If it is decided that the existing tolling pricing scheme will continue, one could adopt the simpler solution of using a combination of ANPR and RFID at existing toll plaza locations. We could continue with existing FASTag systems and build on the effort made in this direction so far.
On the other hand, if the future is expected to see a transition to distance based pricing, a suitable black-boxes-in-vehicles solution is the way forward. Then the question becomes how such a system would optimally look and how to roll it out without causing major disruptions in the transition period.
