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Rethinking road-widening - Tunnels?

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One of the core infrastructural issues we are facing is an inability of our arterial roads and highways to provide rapid cross-town access. Globally, city and highway planners recognize and create different infrastructure for highways and city roads. See Dr. Joglekar’s posts here for a succinct description of this problem plaguing most Indian cities. A simple schematic (full size image here)and an inventory of city highways reveals the problem.

Thru Highways:

  1. NH7 (in blue)
  2. NH4 (in red)

Terminal Highways:

  1. NH-209 (in yellow)
  2. SH-17 (in green)

While the ORR and the planned PRR attempt to relieve through-traffic, these highways ironically remain some of the fastest cross-town routes. Recognizing this, infrastructural planners have expanded/widened roads leading into the city where land was available and have built (BETL, Mysore Rd flyover), are building (Nelamangala expressway) or planning to build (Balabrooie-Hebbal) long flyovers to ‘jump’ the bottlenecks. As we all know though, these just move the bottlenecks. And so, the ever-unpopular (and time-consuming) appropriation of massive amounts of land and road-widening is being touted as the panacea. There might be another way though.

An alternative

One option might involve reconnecting NH-4 and NH-7 using a belowground access-controlled (NOT signal-free) highway that cuts through the city and ensuring that NH-209 and SH-17 don’t ‘dump’ traffic in the middle of the city (full size image here).


  1. Travelling south, NH-7 would move completely off the existing Bellary Rd after the Mekhri circle underpass moving onto Palace ground property (that might be available). At Cauvery theatre, it would join an emerging NH-4 and then ‘dive’ underground just before Palace Road ‘emerging’ near (or after) the Military school on Hosur Road.
  2. Traveling east, NH-4 would go underground near the IISc Gymkhana ground (potentially before the MS Ramaiah Rd intersection). It would emerge near Cauvery theatre (on Bellary Rd) and join NH-7. After ‘re-submerging’ near Palace Rd, it would travel along with NH-7 branching off (belowground) to emerge near the Bhaskaran Rd/Kensington Rd intersection
  3. Traveling north, SH-17 would go belowground at the foot of the Sirsi Circle flyover  and join NH-4/NH-7 underground.
  4. NH-209 would terminate at ORR leaving users the option of using SH-17 or NH-7 for a cross-town commute.

The project would function best if expressway design standards are consistently adhered to. All project roads should maintain a constant width (preferably 4 lanes + 2 emergency lanes) widening to 6 lanes only in sections where highways combine (e.g. NH-4 and NH-7). A limited number of surface exits could enable rapid access to different points in the city (K.G. Road, Kanteerava stadium, Millers Road/Vidhana Souda, HSRL terminal/M.G. Rd, Kamaraj Rd, Richmond Rd etc). Further appropriately designed interchanges (dark brown squares in pic) would be required to connect highways underground.

Pros, cons and disclaimers:

  • Cost: Similar projects across the world have cost anything from Rs 280 crore (for Sydney’s 2-lane Cross City tunnel to a staggering 66,000 crore (for Boston’s 10-lane Big Dig. However, BBMP’s existing road-widening plan on 6 corridors already calls for an investment of 597 crores.
  • Time: Similar projects have taken anything from 2 years (Cross City tunnel) to 22 years (Boston’s Big Dig)
  • With adequate planning, inconvenience to road users can be minimized with tunneling work starting in areas where no current roads exist (e.g.  Palace Grounds, Ulsoor Lake, SJ Park) emerging onto the surface nearer the completion date. After cross-town connections are complete, exits to surface streets (e.g. K.G. Rd, M.G. Rd) can be added on.
  • Other arterial corridors can (in some cases) be redesigned to filter onto ‘reconnected’ highways. For example, Old-Airport Road can be connected to NH-4 using Suranjan Das Road.
  • This project would not address existing bottlenecks outside the project area (e.g., the Bennigannahalli bottleneck on Old Madras Rd). However, using a consistent road-width 4 (travel) +2 (emergency) lanes and strict access-control throughout would make the highways effective travel corridors.
  • The project does not address surface streets or public transportation. However by reducing current traffic loads on surface streets, roads can be engineered to maintain a consistent (4-6 lane) width, turning refuges and better pedestrian infrastructure. Existing one-ways can be reverted to two-way traffic or provide contra-flow bus lanes.

These ideas are not new to city planners as cities the world over have demonstrated the use of this technology. Will it work for us?

(Image courtesy: Wikipedia)



idontspam's picture

Good analysis, Though I dont

209 users have liked.

Good analysis, Though I dont agree with the pink line connection to NH4 West. There is already a connection via CV Raman Road further ahead. So you get the 2 lanes on your pink corridor with signals at bashyam circle and junctions @ 18 cross and Circle mariyamma temple and you get another 2 lanes via CV Raman road with just New BEL road junction in between. Both meet at IISc jn. SO on surface there is 4 lanes each way available already making it a 8 lane corridor. The idiots at BBMP are trying to expand it to what? 10 lanes? What for? all they need is sensors on the road and some electronic (Cheap LED ones will do) display boards to measure traffic and direct people accordingly. Of course put some lane marking with physical barriers for turn lanes appropriately.

OTOH. If you are planning subsurface corridor it need not follow any of these roads but will only need exits & entry ramps on them. Lets mark out the actual corridor, where it will cross the other mass transit infrastructures, where the exits & entries need to be. If this is done well we can easily work out the total kms and hence the costing. Start a project I will join.

srinidhi's picture

cost factor?

182 users have liked.

Bringing highways into town thru underground corridor is good...probably this chimes with the govts earlier plan to build elevated corridors within then city..however think duddu will be the biggest criteria, more so with the underground setup! 

We know of the recent such projects in the Boston costed them 15 Billion Dollars..and ppl are not sure even now if they will turn profitable anytime soon!

idontspam's picture

.however think duddu will be

208 users have liked.

.however think duddu will be the biggest criteria, more so with the underground setup! 

Nothing will get cheaper anymore. Funding can be arranged if it is an intelligent plan. It cant be a joke like flyovers BBMP announces from time to time. Lets not jump to duddu before working out the solution. Big dig wasnt paid for in cash. Leverage is available in the form of bonds, loans, private participation. If all the politicians black money is unearthed this project can be paid for many times over. So if govt runs out of money we will tell them to dig into their swiss bank accounts. We could petition Reddy's to fund.

I beg to god BBMP doesnt get to build it, it will turn out like the underpass they build, stinking, water logged, roof peeling off and permanantly locked.

Naveen's picture

Cross city tunnels need mgmnt

228 users have liked.

Apart from the huge capital needed for building tunnels, they also need to be managed & maintained well. What we see in our cities is nothing but examples of dirty, broken down pedestrian underpasses, though these are merely some 40 mtrs in length, except for the one at city railway stn - even this may be short of a couple of hundred mtrs long.

The milan subway in Mumbai (Santacruz) floods routinely during monsoon - & this has been the state of affairs there for over two decades now, despite repeated occurrences.

How can we expect our rickety systems to cope with tunnels that are several kms long ? Even our flyovers have started collecting water during showers (like BETL) !

And what about lighting, ventilation, signage ? I think it's better not to think of road tunnels !!

The only exception is rail tunnels, which are managed fairly well, though lighting & ventilation isn't so much of a necessity there.

idontspam's picture

Management? Maintenance? What

193 users have liked.

Management? Maintenance? What is that? There is swiss challenge, swedish challenge etc for making money on infrastructure construction. For maintenance there is only pourakarmika challenge.

Transmogrifier's picture

Of money and Mgmt

215 users have liked.

@ Naveen, I agree it is pretty astounding that BETL needs to be shut down in the face of rain well within the normal range of the monsoon.

Source: DNA

However, IMO that should not preclude from at least conceptualizing something (proper NH connectivity) that should have been implemented decades ago. Even planned or under-construction expressways (Chennai-Bangalore, BMIC etc.) are going to completely ineffective without a rapid cross-town connection. Also, I feel this potentially bolsters what literally is the available room for PT. All our 'widened roads' and one-ways can be more sensibly  engineered (synchronized signals et al.)

@ srinidhi, duddu is never going to be a problem. They seem to have no issue finding the 6k odd crores for the HSRL. Reduce that amount to 4200 crores and you have the 4.5 km long Dublin Port Tunnel.

@ IDS, The only reason I would shy from using a combination of CV Raman Rd and Sankey Rd is that, it would, with some effort end up being what BBMP happily calls a signal-free road and not a true access-controlled road. Unless you mean flyovers and underpasses along the road. Then again, consider the visual impact of that!


PS: Anyone notice the complete absence of a merge zone for traffic entering BETL in the pic and people walking on it... then again maybe I'm nitpicking!


idontspam's picture


203 users have liked.

 with some effort end up being what BBMP happily calls a signal-free road and not a true access-controlled road

If New BEL road jn & IISC/Ramaiah rd jn got a underpass, it would be signal free from cauvery jn all the way to NH4 via mekhri circle. Both the above are T jn's and the underpass can carry Yeshwantpur traffic. But since the IISc design is not known to me they may be making the signal free from malleshwaram side instead of from mekhri circle side so they can justify your pink line. Have to wait & see.

One other consideration should be what these corridors are serving? If we built the same corridor underground it can take a completely different route and serve a much better purpose of being a road that quickly connects the city NS, EW than just a highway connector. For traffic whose destination is not the city they are better off taking the bypasses and this can be ensured by tolling thru traffic higher than city ones

Interested in making a proper underground proposal and send to GoK? 

Transmogrifier's picture

Purpose clarified

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But since the IISc design is not known to me

Is there a planned 'signal-free' corridor along Sankey Rd? And if so, is that what you mean?

Here's where I see the purpose. In my mind, these cross-town connections are essentially what you're hinting at. They are in their very essence NS/EW connectors. However, the reason that (atleast in my head) they mostly conform to their existing routing is to enable access to the CBD. An exit near the Chinnaswamy stadium, for instance, would work really well with the planned HSRL station on M.G. Rd. Similarly exits near Ambedkar Veedhi or K.G. Rd (via an SH-17 connector) are all aimed at providing rapid radial access.

At the same time, I do also visualize these as highway connectors. Take Jacksonville in Florida (U.S.) for instance.

If you were driving North on I-95 and not intending on stopping there, you would probably take I-295 which circles the city (like our very own PRR is expected to do). However, if you live in Jacksonville, and want to go 'into town' you could still use I-95 which cuts through the city. Similarly, if you were driving East (into the city), I-10 ends in I-95 and not abruptly with a signalized intersection. This is what a SH-17 connector, in our case, would achieve.

A proposal? Sure.. there's a lot right here (on Praja) that can be used as material.


silkboard's picture

good idea, key drivers to back this ...

218 users have liked.

Key drivers to back one big idea like this would be

  • Converting long standing highways inside the city area into real signal free corridors is a mythical chase.
  • Except for Outer Ring Road (most part of it) which is a "new" road, all big radial corridors are business roads for long time now, and have lot of activity rooted along the "ribbon", "tributaries", and pedestrians.
  • You can't change long rooted "ribbon" (adjoining the proposed signal free corridors) usage patterns by just removing signals and making flyovers at few junctions or tributaries.
  • Foget widening and all (and the tree cutin and pavement eating projects) to attack the ribbon. Only possible way perhaps is to put up fences to keep road area separate from the ribbon. Can anyone do that today? Heck, closing medians at tributaries here and there itself draws so much protest.
  • Perhaps the only realistic way is to change the usage pattern of the "ribbon" along the target corridors by relocating businesses elsewhere. And that we know is also a very hard task, much harder in the CBD today.

Conclusion: Usage pattern of ribbon area is what makes it hard to make signal free corridors. Flyovers and widening CAN NOT alter that.


  • There is a need. You need fast North-South and East-West connection to move goods and cross town traffic. One "+" in between the Outer Ring will do.
  • This is all you should give to the fans of private transport. One such smooth option, and that's it. No more flyovers and road widenings, and court cases for accompaniment.
  • CTTP had proposed few long elevated stretches - Madivala to Shoolay circle, Kundalahalli to I think somewhere past Domlur and two more. So, there is a good data based way of finding the exact route of this "+" in the Outer Ring.
  • Put up long elevated sections, or tunnel roads (as Transmogrifier has proposed here) and be done with it.


Transmogrifier's picture

Nailed it...

196 users have liked.

@ SB...exactly. It is unreasonable to wish away ribbon-development. Also, 'tunnel roads' might be preferable to expanded surface streets in the heart of the 'CBD' because it gives you the flexibility to plan a genuine access-controlled 4 lane rd (with interchanges (such as Sydney's Cross City tunnel)...

... and yet visually, have minimal impact. All exits to surface roads can just be a lane wide.

And with a little bit of foresight and planning (which admittedly is the hardest thing to find nowadays), safety can be appropriately planned for...

Image copyright: (Dublin port tunnel)


@ IDS, I forgot to mention that having pink (NH-4) and light blue (NH-7) run together for 3-odd km could save a ton of money (even if this section is a tad wider.

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