COMMENTS

Hi Sanjay,

Thanks for your feedback. I certainly may have missed certain traffic streams since I had just picturised it in my mind. I have created a rough sketch of the lanes to get a clearer idea, which is shown below. Please click on the image to get a bigger version. It is hosted in Flickr. I have omitted the curve in the road to make it simpler.
I created the picture using the drwaning tool in Microsoft word since I didn't have a better tool available. It isn't great, but should convey the general idea of the traffic flow.



This is a rough sketch and not to scale, since I don't have access to the detailed plans. I have shown only two lanes on the service roads. However it is possible that between the two signals, it is possible to have an extra lane under the flyover, provided the flyover is high enough.

Since the Agara junction has survived all these days with only a traffic island and without signals, it could probably survive in future also without signals. The whole middle section under the flyover from 24^th main to 27^th main can be treated as one big traffic island. However the bus lanes in the middle will complicate things and signals are required for safety reasons and also to provide priority to buses.

The signals at 24^th main and 27^th main certainly needs to be synchronized. To reduce the cycle time at the 24^th main signal, the traffic coming from Koramangala and wanting to go to Silkboard or 24^th main, can be forced to come to the junction of 27^th main and make a U-turn. Anyway the amount of traffic from that direction is low. Also traffic coming from HSR 27^th Main and wanting to go towards Iblur can be forced to go to the 24^th main signal and make a U-turn. (It is sort of like that even now; there is a sign installed at that junction to that effect, however most people ignore the sign and just take a right turn at 27^th main.)

I also observed that the service road in front of Sobha apartments at the 27^th main junction needs to be made a two way street. That is the only way the Sobha residents will be able to get into the ORR towards Silkboard. There are also a few shops on that service road and they need to be provided a way to go towards Silkboard.

Come to think of it, the same situation will apply to the residents of the service road near 24^th main, adjacent to the temple, if they need to go towards Iblur. But those people can at least go towards Silkboard, get into HSR layout and come out through 24 main or 27 main.

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Guidelines for Horizontal Curves -IRC: 38-1989

My own formulae:

1.0 The IRC restricts the superelevation to 5.0%

but is silent on the speed.

e.g. if the superelevation required for 60kms /hrs is 10.0% than

it can be done upto 5.0% practically, IRC does not laydown guidelines

for the speed to reduce or increase.

2.0 Also providing the max allowable superelevation may have 

adverse effetcs on the bearings of the bridge superstructure.

This was just a first impression,

there are various remedial measure one is speed

other is extra widening, not allowing slow moving vehicles etc..

nJ

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Iblur Intersection

It is now clear that a single 3-lane ramp is going to be positioned here for vehilces arriving from Maratahalli & proceeding towards Silkboard to jump over the intersection without any conflicts. A service road on the left of the ramp allows those vehicles that would want to turn to Sarjapur.

The other direction of travel along ORR does not conflict with any other flow & does not need an elevated ramp. Therefore, it has been retained on the surface.

Only one traffic conflict will remain - vehicles arriving on ORR (from Silkboard) & proceeding towards Sarjapur will conflict with those that arrive from Sarjapur & want to turn to ORR towards Marathalli. This can be regulated easily with traffic signals, which should include a phase for pedestrian crossing.

The need for a roundabout will not be necessary as traffic conflicts are too few.

Agara Intersection

The two ramps allow uniterrupted flows along ORR, thus removing bulk of the traffic, whilst left service roads take care of traffic joining or leaving ORR to & from Koramangala. A traffic signal would become essential to regulate conflicts below the ramps (eg. traffic from Koramangala turning into ORR towards Silboard conflicting with those that arrive from Iblur & proceeding towards Koramangala, bus movements at surface, etc.).

The median surface bus lanes is a good option provided pedestrian access is included in the signal phases & traffic calming measures are in place (speed breakers, signage, etc).

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The bridge plans are good..what about pedestrians and the traffic planning below the flyover?

As we understand there are too many projects which have been built in bangalore with peds no where in the plan and traffic below the flyovers is always a mess and we live with the incomplete planning for years!

Lets see/make a more comprehensive plan for this!

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Since, the flyover at the agara junction is complete now and all functional. Its not my regular commute road, but I have been through this route quite a few times in past few weeks, and so thought of waking up this thread again.

There are couple of issues here -

(1) Road below the flyover, be it from koramangala to Iblur side, or service road (now main road) in front of the sobha & other apartments, were not at all recontructed again after being damaged while flyover construction. They are not at all safe for motorists at all.

(2) Also, nothing is being done for pedestrians also, the drains cover along the service road is also not complete.

(3) Commuters waiting for buses at bus-stops below the flyover also stand in patches here and there, buses doesn't stop at designated stops.

(4) No priority for buses at all.

(5) Bus drivers and even other drivers (want to go towards koramangala) also block all the lanes at the signal, blocks all the straight traffic as well.

(6) Traffic coming from Iblur, wanting to take that single lane road at the start of the flyover, huge jam happens, because of the bad design of the flyover. It blocks traffic going on the flyover as well, as 2 lanes are waiting to enter into 1 lane below the flyover.

I suggest, need to visit this place and have a review.

BDA is all completing flyovers but not a single flyover, they had repaired (if not re-constructed) the roads below and around the flyover, which got damaged during the construction.

Deepak

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