Hosur Road : 4 lanes better than 6

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.

Suhas,

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.

 >>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.

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.

 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.

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.

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 !

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.