Bengaluru Tunnel Road (Hebbal to Silk Board): What It Means for Property Buyers

On a weekday morning, the stretch from Hebbal flyover down Bellary Road, onto the Outer Ring Road and toward Central Silk Board is one of the most reliably jammed corridors in India. A drive that should take 25 minutes routinely swells past an hour. So when the Karnataka cabinet cleared an underground answer, Bengaluru paid attention.

The Bengaluru tunnel road answer to that misery is a 16.74 km link from Esteem Mall Junction at Hebbal to the Central Silk Board Junction in the south. The Karnataka cabinet greenlit the North-South Corridor in May 2025 at an approved Rs 17,780 crore, under a Build-Own-Operate-Transfer model. For buyers along the spine, from Hebbal and Bellary Road through the Outer Ring Road to Silk Board, the temptation is obvious: a tunnel that bypasses surface traffic could reprice everything above it. The catch is that this road is years from carrying a single car.

The short answer. Bengaluru's tunnel road is a 16.74 km Hebbal to Silk Board project, approved by the Karnataka cabinet in May 2025 at Rs 17,780 crore under a BOOT model with tolling rights for the concessionaire. The trade-off: the lowest construction bid came in far above the government estimate, the cabinet has not yet awarded the contract, and even on a clean run the tunnel is unlikely to open before the end of the decade. Prices may run ahead of a road that does not yet exist.

Quick facts: the Bengaluru tunnel road (Hebbal to Central Silk Board) is 16.74 km long, was cleared by the Karnataka cabinet in May 2025 at an approved Rs 17,780 crore, and will be built and tolled under a Build-Own-Operate-Transfer structure, per Deccan Herald and The News Minute.

What exactly is the Bengaluru tunnel road from Hebbal to Silk Board?

It is a 16.74 km underground corridor connecting Esteem Mall Junction at Hebbal with the Central Silk Board Junction in the south, letting cars bypass surface congestion on Bellary Road and the Outer Ring Road. The Karnataka cabinet approved the North-South Corridor in May 2025 at Rs 17,780 crore, in two packages.

The project sits inside a wider menu of Bengaluru infrastructure ideas, including additional tunnel segments and double-decker flyovers. The Hebbal to Silk Board leg is the flagship because it targets the most painful north-south journey in the city, and it is being executed through Bengaluru Smart Infrastructure Limited, a special purpose vehicle for large city projects.

Two points matter for buyers. First, this is a car-only road, not a mass transit line, so its benefit is concentrated on private vehicle commuters. Second, it is an underground bypass, so it will not create new frontage, retail strips, or station catchments at street level the way a metro corridor does.

How much will it cost and who is building it?

The approved cost is Rs 17,780 crore, and the model is Build-Own-Operate-Transfer: a private concessionaire builds the tunnel, recovers its money through tolls over a long concession, and eventually transfers it back to the state. Per Deccan Herald, the structure grants toll collection rights for 30 years, extendable by a further 10.

Four firms bid before the tender closed: the Adani Group, Rail Vikas Nigam Limited, Dilip Buildcon, and Vishwa Samudra Engineering. After technical evaluation, the financial bids were opened, and the Adani Group emerged as the lowest bidder for both packages.

Here is the problem. The Adani Group's lowest bid came in at about Rs 22,267 crore, exceeding the government estimate by roughly 24 percent on the first package and 28 percent on the second, per The News Minute and Deccan Herald. That gap matters most for buyers: the project as bid is more expensive than the version the cabinet approved, and the state has not yet decided whether to accept it.

What could the tunnel road mean for property along the north-south spine?

If the tunnel is built and opens, it could ease the congestion penalty that caps demand at the ends of the spine, a positive for locations near the portals at Hebbal and Silk Board. A faster link between north Bengaluru and the southern tech belt could make homes at either end more liveable.

But the mechanism is narrower than buyers assume. Because the tunnel is underground and car-only, it does not create street-level value the way a metro station does. There is no new high street and no pedestrian catchment. The benefit is travel-time, and it accrues mainly to car-owning commuters willing to pay a toll.

North Bengaluru already has a stronger demand story driven by Kempegowda International Airport, established employment, and metro expansion. For the fuller picture, see our coverage of the north Bengaluru real estate market in 2026. The tunnel is best treated as a possible accelerant to an existing story, not as a reason to buy on its own.

When will the Bengaluru tunnel road actually be ready?

Not soon, and not on any date a developer brochure should promise. As of mid-2026, the cabinet has not awarded the contract, because the lowest bid exceeds the approved cost and the government is reviewing whether to accept it, rebid, or restructure it.

Even with a clean award later in 2026, construction of a tunnel this long runs into years, with reported completion windows of roughly 36 to 48 months from the contract date. That points to commissioning toward the end of the decade at the earliest, and large tunnelling projects in Indian cities routinely slip past their first timelines.

For a buyer, the translation is simple. Any premium you pay today for tunnel access is a bet on delivery that is several years and one unresolved cost dispute away. The gap between cabinet approval and an open tunnel is exactly where speculative pricing gets ahead of reality.

How does the tunnel compare to other Bengaluru transport plays for buyers?

It is one option among several, and for most buyers not the strongest. Metro lines generally create more durable, broad-based property value than a tolled car tunnel, because they serve more people and reshape the street above them. The table below sets the tunnel against other corridors on the north-south axis.

The honest reading is that the tunnel reinforces locations that already have a reason to exist, and is unlikely to rescue one whose only argument is the tunnel itself.

What are the real risks and trade-offs buyers should weigh?

The biggest risk is paying for connectivity that arrives late, costs more than billed, or in an altered form. The cost overrun in the lowest bid is a live warning that the economics are unsettled, and a BOOT toll structure means the benefit comes with a recurring charge.

Beyond cost, large tunnelling projects raise funding, environmental, and land questions that can reshape alignment, portals, and schedules. The exact portal locations at Hebbal and Silk Board matter far more to a specific plot than the headline route. Tolling also dampens the everyday benefit for price-sensitive households who may keep using surface roads.

There is also an opportunity cost. If you are buying mainly for connectivity, an operational metro station within walking distance is a more bankable asset today than a tunnel portal that may open in 2029 or later. Our note on the Satellite Town Ring Road link between Hoskote and Hosur shows how much of Bengaluru's road future is still under construction.

So should you buy near the tunnel route now?

Only if the home stands up on its own fundamentals first, with the tunnel treated as upside rather than the reason to buy. Look for a location that already has jobs, social infrastructure, water and power reliability, and ideally an operational transit option, then let the tunnel be a bonus.

If your purchase only makes sense on the assumption that the tunnel opens on time and lifts prices, you are taking on the full delivery and cost risk at today's prices. That is the classic trap of buying on a promised road. The smarter posture is patience: watch for the contract award, the final alignment, and the portals first.

A seven-point buyer checklist before paying any tunnel premium:

1. Confirm the cabinet has actually awarded the construction contract, not merely approved the project in principle.
2. Check the final tunnel alignment and the exact Hebbal and Silk Board portal locations against the specific plot you are considering.
3. Verify the project cost the state finally accepts, given the lowest bid exceeded the approved Rs 17,780 crore.
4. Treat any stated opening date as provisional and assume slippage of a year or more.
5. Confirm the home stands up on jobs, water, power, and social infrastructure without the tunnel.
6. Compare against an operational metro or arterial option that exists today rather than a tunnel that does not.
7. Check the project's RERA registration and approvals on the Karnataka RERA portal before booking.

Is the Bengaluru tunnel road from Hebbal to Silk Board confirmed?

The Karnataka cabinet approved the 16.74 km North-South Corridor tunnel in May 2025 at Rs 17,780 crore under a BOOT model. However, as of mid-2026 the construction contract has not been awarded, because the lowest bid exceeded the approved cost and the government is still reviewing how to proceed.

How long is the tunnel and how much does it cost?

The tunnel road runs about 16.74 km from Esteem Mall Junction at Hebbal to Central Silk Board Junction, and the cabinet approved it at Rs 17,780 crore in two packages. The lowest bid received, from the Adani Group, came in higher, at roughly Rs 22,267 crore, exceeding the government estimate by about 24 to 28 percent.

Will the tunnel road raise property prices nearby?

It could ease congestion at the Hebbal and Silk Board ends if built, which may support demand there. But it is a car-only tolled tunnel that creates no street-level frontage, so its effect is narrower than a metro line. Buyers should treat any uplift as uncertain and several years away.

When is the tunnel expected to open?

No firm date is fixed, because the contract is not yet awarded. Even after an award, construction of this length is reported to take roughly 36 to 48 months, pointing to commissioning toward the end of the decade at the earliest, with a realistic chance of further delay common to large tunnelling projects.

For sources, see Deccan Herald on the BOOT model approval and the lowest bidder for the tunnel road project, and The News Minute on the Rs 17,780 crore cabinet approval.

Buyers comparing the tunnel against rail options can read our coverage of the Namma Metro Orange Line, which lays out how a mass transit corridor differs from a tolled car tunnel in the value it creates. For a project on the Bellary Road spine near the northern portal, see Abhee Bellary Road in Jakkur.

Last updated 2026-06-25. PropNewz Team.