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Hosur Road : 4 lanes better than 6

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[Admin's note: These are the sort of posts that need to be highlighted on Praja - Aggregated or Original analytical work to talk specifics about the problems or solutions.]

This is a sister blog to my previous blog

This blog deals only with the vehicle part (as against footpath/cycle track which please comment solely on the other blog)

Current plan is to have 6 lanes, including median this is around 22m. I am cut pasting IDS comment here -

"This way you get a well engineered 4 lane road with ample ped+cycle infrastructure with trees parking and all. WIth 6 lanes you dont get turn lane, parking, trees and end up with squeezed ped path. If 30 meters not available cut down the parking in those streches, you will get 3+ meters. If still running short cut center lane you will get another 3+ meters. You will still get uninterrupted 4 lanes+ped+cycle.

If turn lanes are required only at the junctions that space during the rest of the strech can be allocated for a wider median with trees on it or for parking on the other side or for a wider sidewalk or even for bus bays. But it is important to have consistent lanes all through"

This has been developed more in the attachment.

Bus bays have been seperately provided for - pls leave that from this discussion for now.

Hosur Road StreamLining.pdf269.3 KB


silkboard's picture

Excellent stuff, though so obvious

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Not that BBMP engineers don't know this. I have heard them only say, that throughput of a long channel depends on the width of the narrowest sections. In fact, a channel with changing widths (4-6-4-6 lanes) would actually produce less throughput than a consistent narrow channel (4 lanes all through) because the merges and de-merges would produce unwanted "collisions" at the points where width would change.

It is better to have 4 lanes consistently, and use the extra width for road side and traffic management amenities like "protected turns", "holding" lanes (on top of ped/biking space as needed).

Since most readers are not likely to open and read the attachment in this post, let me pull out two pictures from the PDF Suhas has shared above.

Here is the picture showing holding lane to segregate right-turn awaiting traffic from the flow. This is pretty obvious stuff to implment, it's time follow these for corridor improvement projects.

silkboard's picture

Holding lane for left turn

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One more picture from Suhas's PDF. This one shows waiting lane to hold traffic turning left.

The extra road width can similarly be used to provide merging lane for traffic that would come in to the corridor via "free left turns".

Naveen's picture

4 or 6 lanes - Depends on Width at Intersections

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Very right - 4 continuous express lanes with additional turn lane/s (at intersections) will result in much smoother & higher throughputs than 6 lanes with no provision for turn lanes.

During the previous discussion, you mentioned about 4 magic boxes that are being included on this stretch. Provision has to be made for turning traffic in way of these magic boxes too. I doubt if they are planning substantial land acquisition at /adjacent intersections to provide 8 lanes at these spots. If so, then, uniform 6 express lanes may be possible.

idontspam's picture

Very good illustration

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If there cant be land acquisition for 8 lanes at the magic boxes then considering 1 lane for exit/entry ramps the magic box is probably carrying 4 lanes only as throughfare. It then becomes imperative not to have 6 lanes all the way and then squeeze the through traffic to 4 at the magic boxes. The merge problems will haunt again. Buffer/holding lanes work best when they open up at junctions in addition to existing carriage way like in suhas illustration. That way cars in the flow pull away into spare holding space freeing up the space for through traffic. Not that one cant dedicate the third lane for exiting traffic all the way with attendant merge problems, but that the space can be used for other features like parking/ped/greenery etc while being able to maintain smooth flow.

One can always try these with markings and bollards

srkulhalli's picture

Thanks : Praja can be a great bouncing board

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Thanks SB,  I think Praja can be a great board to bounce ideas, thoughts etc. I put up my plans here and depending on feedback( IDS, Naveen, others - good feedbacks) , fine tune/modify before I take it forward. In fact I was suggesting the same to CityConnect guys,  and at some stage we should promote that concept across. For eg: no harm for BMTC or METRO to put in their plans for bus services, routings, websites etc and use any good quality feedback that they can get out of here

On the other point :-I know the concept is obvious, but am not sure how much particularly the engineers were aware of it, at least it did not show up on their plan.  I tried to explain with pen and paper, but was not sure how well it was received. That is why the trouble to do the drawings :)


srkulhalli's picture

Signal free neccessary for Hosur Road

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I make this point because there has been a lot of discussion on this and magic boxes at different places. I am trying to address all of it here and make a case for what is planned.

In any big city, irrespective of all the other things, we do need certain roads which can take a high capacity (a.k.a freeways in US). Not all roads need to be this way - just some select arterial roads/ corridors. And the only way to get them to higher capacity is to make them obstruction free (no signals, pedestrians on it etc). There is a limit to how much creating more lanes or better design can do, beyond it signal + obstruction free is required.

Now in an ideal scenario, this should have been planned well, space apportioned for service roads, roads should be grade seperated to whatever extent possible etc. Now that has not happened, and some roads have become major arterial roads which were done without much forethought.

We have what we have - and the only way out is to either have a grade seperated road all along (BETL types) or flyovers or magic boxes. Magic boxes is the cheapest option and though it is a patchwork solution, it is a solution.

Again, one point raised is on speed. The idea is not to provide for fast traffic or encourage fast traffic. Idea with the magic box solution is not to slow down traffic. There is a difference !

This is irrespective of we need to improve Public transport, pedestrian facilities etc - each needs to be done in its own space and should not be mixed into this.


srkulhalli's picture

Magic box and intersections

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Land aquisition is planned only for 30m. Of this 4m on each side is dedicated to footpath + cycle track - and we dont want to touch that :) So that leaves 22m, which is just about sufficient for 6 lanes.

So if we want to keep the 4 lanes through - and that goes through the magic box - that leaves one lane for entry / exit. on either side Do you see too much of an issue with that ?

Let me see if I can get their plan for magic boxes next time.



idontspam's picture

Confirms my fears

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 but am not sure how much particularly the engineers were aware of it, at least it did not show up on their plan.  I tried to explain with pen and paper, but was not sure how well it was received

This statement confirms the fears I had all along. I didnt think they knew at all and i dont think they still do. I was not surprised they dont know these or even if they had it would have sounded like something they couldnt wrap their heads around.

Naveen's picture

4 Lanes Better

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If 30m is all that is going to be available throughout, I think the road should be restricted to 4 lanes to allow sufficient room for other utilities such as bus bays, turn lanes, green areas, pedestrian islands, etc.

Where magic boxes are to be fitted, additional spaces on sides will be available since the 4+4m can also be utilized at turns to allow for 2 lanes without further land acquisition. Just a single lane at turns (ie. abt 3.5m) will not be sufficient. What width are these magic boxes ? I think they are likely to use ones with 6.0m internal width x 2 nos. This should still allow enough room.

Based on this, I think you can make a plan. I hope the BBMP engineers mean it when they say that 30m will be made available throughout.

parisarapremi's picture

Lane curve at intersections

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    Wonderful diagrams ! Even a kid can understand this scheme. The engineers at BBMP should be not have problems comprehending ;-) In cities like Dallas, I have seen this very same arrangement and the whole scheme works like a charm.

    Agree that four lanes is all we can get even on a six lane carriageway. The extreme left lane in general is used for parking /stopping etc anyways.

     From the diagrams above, it looks like the straight through lanes curve a little at the intersections. Is that intentional ? I hope not as drivers dont really follow the lane. Its better them straight throughout.

     However, do we expect our drivers to really honour the left only or right only lanes ? There is always a chance that an auto or a bunch of two wheelers land up on the straight lanes blocking traffic for the folks who need to proceed straight. How do we avoid this ? Even adding a barrier for the turn lanes does not help much as congestion gets created at the point the barrier starts. (Manipal hospital U-turn on Airport Road is a good example)




skumaras's picture

Making drivers honour turn lanes

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 >>However, do we expect our drivers to really honour the left only or right only lanes?

Drivers can be made to honour the turn lanes by fining the errant drives heavily. However since stopping drivers at junctions to fine them will create a nuisance for other drivers, another way to control them is to force the drivers (by posting traffic wardens at junctions) to take the left or right turn depending on the lane they are. Once a few of them get inconvenienced enough to take the wrong turn then needing to make a U-turn to get back, and thus lose some time in the process, they will learn. After a while they will get into the habit of staying in the correct lane.

Naveen's picture

Correct Infrastructure First

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I agree with skumaras - The chaos we see is because the road designs are not well engineered. Proper infrastructure has to be in place first, & once this has been done, better enforcement is possible & can be easier.

silkboard's picture

1 more vote for skumaras

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Consistency in designs and signage is a must, I would say that it comes first. Otherwise we can never break this deadlock between enforcement first or design improvements first.

If you don't buy the argument that design improvements come first, and aid in enforcement, just do this. Pick two sections of wide enough roads, 1 with with clearly painted direction divider, another with no direction divider at all. You would notice that simple and clear line drawn in the middle helps to keep a larger number of drivers on the right (as in the left) side of the road.

With clearly marked lanes and signages, you also take out a lot discretion from the hands of the cops who would fine you. How would one defiine rash driving? With clearly available left turn hold or right turn de-merge lanes, you have one definition right away - rash lane change before turn. Think more like this (think no-parkking zones or signs) - design improvements will be of great aid to cops.

E.R. Ramachandran's picture

Lane fpr Ambulnaces, fire- fighters

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Thanks for great writeup, pictures and comments. One comment though.

We do not keep a lane for emergencies like Ambulances and fire-fighting trucks where a delay means  loss of life/ lives, property etc.Most times  we see Ambulances hollering  amidst traffic on all sides. Can something be done in this regard?

idontspam's picture

Emergency vehicles

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 We do not keep a lane for emergencies

Ambulances are allowed to use the shoulder on highways, and on surface streets they are allowed to use the wrong side in case of jams and throughout the world including even in India (yes I was surprised) it is clearly specified in the rule books for private vehicles to move over and give way to emergency vehicles which indicate the emergency situation by clearly visible (flashing lights) and audible (siren) signals. Fire force in some countries are allowed to slap tickets on private vehicles for obstruction of emergency vehicles unreasonably.

One, move over is not happening right now because we pack the road like sardines with utter disregard for lane rules (where little they exist). If we kept to our lanes there will be wiggle room one can actually pull over and give way. If you stuck to your lane you would have noticed an auto or an omni squeezing between and blocking that space also.

Two, Our ambulances especially are little more than glorified taxis, except for a handful these ambulances dont have qualified medical personnel or equipment to provide that first level assistance on location to save lives before they can be shipped over. 

Three, It is important to note that, in case of an ambulance atleast, technology can bring the hospital to the patient if one really builds & deploys true lifesaving ambulances, instead of running omni taxis. Traffic will then not be an issue at all.

sanchitnis's picture

Bicycle Group commute - Silkboard Jn to E-City on 04-Sep-09

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Thunderbolts - The Infosys cycling club has organized a ride
from Silkboard Junction to Electronics City as part of monthly group commute to work! They will be happy with the new design suggested!

srkulhalli's picture


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I agree with Skumars-SB and it is a very relevant point -

Without having a consistent and well executed road infrastructure, the compliance will not be there. There is no point in expecting lane based driving if lanes dissapear halfway, or expecting people to obey signage if they have been thoughtlessly put up. As an example, I violate a one-way sign every single day. I observed it for a few days, until the policeman on duty was diverting traffic through the one-way. The sign just didnt make any sense, and everybody was better of ignoring it. Point is you have many signs like there, and eventually they command less respect, and then the "correct signs" also get violated.

The other aspect is it needs to be everywhere - a single strech of road is not enough to change driving patterns  - but if it is consistent across the city - the message gets ingrained in the drivers, it starts becoming a subconsious habit and thats when good compliance starts setting in,

Of course, this needs to be followed by training  and still there will always be the rule breakers, so enforcement. is neccessary But enforcement is on the top of the pyramid - you can enforce only so much as the quality of the road engineering


srkulhalli's picture

Road legacy issues

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@ Naveen, They have got 30m for a lot of the strech, but not all - the usual land acquisition issues in some streches.

@Ramachandra - very good point, but no good solution for emergency vehicles. Pretty much agree with IDS, the way around is to use technology to extent possible. After the struggle to widen road, you will have only two lanes, of which if one lane is marked for emergency vehicles nothing is left. Roads are one thing were legacy plays an all important role - very difficult to change once development has happened along the road - hence long term planning is absolutely critical.

Dont know if you have tried using the emergency service - I tried once - nobody lifted  the phone - there are even more basic problems to solve there.

@parisapremi - Dallas is a different story .. they have so much land they cannot figure out what to do with it - even the inner roads which have practically no volume are sometims 6 lanes with wide median. We will have to make do with the legacy that is there.

Compliance has been discussed. To add, I liked one statement which was in IRC - 'Design should be based on what the driver is likely to do, not on what you want him to do' . If we design turning lanes such that they are the most convinient way of turning, the number of violations are minimised.



Naveen's picture

4-Lane road - Or chaos ?

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the usual land acquisition issues in some streches

If this is the case, I dont see how we can plan a well designed road with turn lanes, etc.

If the court/s favor land owners, we will be back to square one & the road will be messy, like any other. However, if BBMP is sure of getting pocession of 30M land throughout, it may be sensible to design it, as planned based on this assumption.

Design should be based on what the driver is likely to do, not on what you want him to do. If we design turning lanes such that they are the most convinient way of turning, the number of violations are minimised.

Agreed - this is correct for roads that handle traffic upto it's designed capacity, not higher.

When traffic volumes keep increasing & go beyond designed capacities, the drivers will do whatever possible to speed up their travel, resulting in chaos as we have been seeing.

idontspam's picture

Asphalt or geometry

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 I dont see how we can plan a well designed road with turn lanes, etc.

But this is all the more reason to keep it to 4 and not 6 lanes. The point of the whole exercise is  to emphasise fixing the geometry of the roads is more important than adding lanes.

Naveen's picture

Geometry when land is constrained ?

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fixing the geometry of the roads is more important

Near Vellara Jn (till past the left turn towards St.Philomena's hospital rd), there are commercial establishments & there are only 4 narrow /cramped lanes. Adugodi area is another long stretch where 4 proper /standard lanes may not be possible, let alone 6 lanes. Also, there is a '+' intersection at it's narrowest part. At Koramangala (forum mall) again, the existing 4 lanes are cramped, as also at Madiwala police station - both these locations also have T-junctions. These are what exist now without any provision for turn lanes.

So, how will fixing the geometry work & make it a 4 lane road with turn lanes for intersections where land is constrained & unavailable ?

Going by what you suggest, it might be better to plan a 2-lane road by fixing proper geometry since that would be primary !

idontspam's picture

Geometry vs number

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 it might be better to plan a 2-lane road by fixing proper geometry since that would be primary !

And my point being, wouldnt that be better than 6 lanes in small streches? 

idontspam's picture

Protected turn

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Have you noticed how we dont use Protected (right) turn system of traffic lights on our roads? How does that impact traffic flow? Why havent we switched to a protected turn when the rest of the world has?

PS: Have you noticed at some manually manned intersections the constables implement the protected turn to handle traffic efficiently.

Hrishi's picture

Hosur Road - Checkpost Signal

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For the last couple of days, I have observed the following at Checkpost signal on Hosur road.

- More number of vehicles are waiting to take a U-Turn or a right turn towards St. John hospital staff quarters.

- Vehicles trying to utilize the new two-way system towards Madiwala are pushed to the left lane leaving very less space for traffic going towards Sarjapur. As Buses are supposed to use this route, there is a bigger traffic block.

Just wondering how this traffic can be streamlined.
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