- The Karnataka state government has planned a mega two-corridor tunnel road project in Bengaluru and will stand as guarantor for the city corporation to take an initial loan for the project.
- The tunnel roads are intended to decongest the roads, but a study refutes the claim, showing that they would carry few passengers than public transport such as the metro or suburban rail.
- Mobility analysts say the project is prohibitively expensive, and the priority should instead be on boosting public transport.
With traffic increasing over the past two decades, the city of Bengaluru has been awaiting a robust public transport ecosystem to decongest its roads. But is the mega, Rs. 400 billion, two-corridor tunnel road project that is being pushed by the Karnataka state government, the solution? Advocates for sustainable mobility say that this project will promote private vehicles and drive ridership away from the mass transit buses, the metro and the suburban rail.
The state government is committed to this controversial project as expressed by Chief Minister Siddaramaiah in his budget speech in the first week of March. He announced that the government will stand guarantee to the city corporation, Bruhat Bengaluru Mahanagara Palike (BBMP) for an initial loan amount of Rs. 19,000 crores (Rs. 190 billion) to undertake the tunnel road project.
Two corridors
To be constructed on a Build-Operate-Transfer (BOT) model, the 40 km-long tunnel road project will feature two corridors: An 18 km North-South corridor connecting the Hebbal flyover in North Bengaluru and the Silk Board Junction in the South. A second 22 km East-West corridor linking K.R. Puram in the city’s East with Mysore Road in the West.
The tunnel roads will run under the Outer Ring Road (ORR) and are intended at decongesting the ring road. However, a simulation model study by the Indian Institute of Science (IISc) Sustainable Transportation (IST) Lab has deflated this claim. The study found that the tunnel road with a 3.5 m width would only carry 1,200 Passengers Per Hour Per Direction (PPHPD) compared to a nine-car coach metro with a capacity of 69,000 commuters. The metro, built with the same cost, would be 40 times more efficient.
The cost dynamics too favour a mass transit option. Compared to the metro’s average estimated cost of Rs. 500 crore per kilometre and Rs. 110 crore per km for the suburban rail, the tunnel road will be prohibitively expensive at Rs. 1,000 crore per km. “Besides, the plan is to make it a toll road, with users paying almost Rs. 330 per trip. So, it becomes an exclusive space for people who can afford a personal four-wheeler. Accident-prone two-wheelers will be banned just like the way it was enforced on the Bengaluru-Mysuru Expressway,” says Ashish Varma, the IST Lab’s Convenor for Transportation Systems Engineering Cell.
The tunnel project is seen as another telling example of a motorist-focused mobility policy followed by successive state governments. The Bengaluru Metropolitan Transport Corporation (BMTC) operates a fleet of about 6,300 buses, grossly inadequate for an estimated population of 1.35 crores (13.5 million). Mobility analysts say the city will need at least 17,000 buses of multiple capacity ranges to activate a definite switch from private vehicles to public transport. Only a fleet expansion of this proportion can boost trip frequencies, schedule reliability and offer predictable first and last-mile connectivity.
Reiterating this, Shaheen Shasa from the Bengaluru Bus Travellers’ Forum says the focus should clearly be on more buses. “The tunnel is a misplaced priority, but they are trying to push through a failed paradigm. How long does it take to understand this simple, well-established fact about a public transport push, traffic planning and management? The tunnel is a waste of money. What happens when this tunnel fills up, how long will they keep doing this? It is like flogging a dead horse,” she says.
A senior Karnataka state police official with several years of experience in managing Bengaluru’s traffic acknowledges this. Preferring anonymity as he is not authorised to speak to the media, he says, the construction of the tunnel roads will take a long time and by that time, the city’s characteristics would have changed drastically and could pose many challenges.
Shift to private vehicles
Private vehicles have increased in recent years in Bengaluru. Karnataka Transport Department data, updated till February 28, 2025, shows that the city has a total of 25,25,449 (2.5 million) registered private cars and 82,43,582 (8.2 million) two-wheelers. Exactly four years ago, on February 28, 2021, this number stood at 2.07 million and 6.6 million two-wheelers.
Anecdotal evidence and metro data also shows that the recent hike in metro fares has further pushed the switch from public transport to personal vehicles with daily ridership falling by 100,000, since the fare hike, as shown by Bangalore Metro Rail Corporation Limited (BMRCL) website data.
An analysis by the World Resources Institute (WRI) India, based on general transit feed specification data from BMTC and BMRCL, indicates that by 2031, 24% of the population within the city’s BBMP limits may still not have access to any form of public transport service within 30 minutes from their point of origin.
Read more: In the fare-play business, Namma Metro has misplaced its priorities
That the tunnel road alignment runs along planned metro lines adds another layer of complexity. As independent mobility consultant Satya Arikutharam points out, “Exactly parallel to the tunnel is the Phase 3A of the proposed metro with 28 stations. That is far more efficient. That (metro) is for people, while this is only for cars.”
Tunnels only temporary relief
The anticipated reduction in congestion on ORR after commissioning the tunnel road will only be temporary, notes Varma. “This is inevitable, because the number of vehicles is growing at a much faster pace. There are almost 3,000 new vehicle registrations per day. Also, the car ownership is 160 cars per 1,000 population for Bengaluru. This is much below the saturation level in any rich country which is about 800 cars. So, you will keep adding vehicles as more road infrastructure is added. The impact of the tunnel road will be very short-lived,” he explains.
The tunnel road project has raised concerns from an environmental perspective too. The Detailed Project Report (DPR) had maintained that the project does not require an Environmental Impact Assessment (EIA). But the Alliance for Sustainable Urban Priorities seeks both an EIA and a social impact study, citing several tunnel-related accidents caused by design flaws and poor understanding of the terrain.
In a petition to the Union Minister for Environment, Forest and Climate Change, the Alliance also drew attention to the Pragati Maidan tunnel in New Delhi that had turned dangerous to passengers due to water seepage issues, cracks in concrete and poor drainage. “Considering the tunnel disasters reported from Telangana and other places, a lot of care and precaution is required. The technology to build such tunnels is still evolving, and thus a thorough assessment of its impact is necessary,” says Alliance member and seasoned legal activist for environmental issues, Dattatreya Devare.
Flooding and safety risks
Heavy rainfall often floods poorly-designed underpasses. A tunnel road stretching 19 km could also face this issue. Varma says, “In grade-separated infrastructure, there is no way for commuters to get out. Last monsoon, the Electronic City flyover was completely jammed for hours. The techies had to leave their cars on the flyover and walk for hours to get home. Underground, you can get totally trapped. Think of the extreme stress that people will face.”
Flyovers end up shifting congestion from one junction to the next, and this applies to tunnel roads too. “This is the fundamental flaw with these kinds of grade separators. You let vehicles go past at a fast speed, and wherever they get out or exit from the ramps, they get stuck in a queue. So, wherever the tunnel road has the entry and exit ramps, this will start leading to choke points there.”
Hydrogeologists G.V. Hegde and K. C. Subhash Chandra, in a newspaper article, have flagged another concern related to subsurface geology and the tunnels. The DPR, they say, considered only the surface conditions of urban features and not underneath. They referred to the building collapse incidents reported from the saprolite ridden zones of BBMP’s Ponnaiyar (Dakshina Pinakini river) catchment where geological, geomorphological and geohydrological conditions prevail. Saprolite is chemically weathered rock that makes it soft and soil-like, making the zone bad for tunneling. The tunnel alignment passes through these zones. The groundwater aquifers and surface drainage network could also be disturbed by the project.
Banner image: Traffic congestion on Airport Road, Bengaluru. Image by Rasheed Kappan.
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