July 04, 2009

But how many carts?

Two final thoughts, or trains of thought, about the new Sealink.

1) I would like to know where else in the world you'd find a sign at a bridge that says "No Bullock Carts". Now you know why I wouldn't live anywhere else.

2) Apart from bullock-carts, buses and rickshaws and two-wheelers are not allowed on the Sealink. Which means it is a bridge designed pretty much only for cars.

There are something like 500,000 cars in Bombay. Say one to a family of 5 -- itself generous -- and you've got a bridge catering to 2.5 million Bombayites. Out of somewhere between 15 and 20 million who live here.

Or consider a back-of-the-envelope calculation. (What's below is taken largely, and lazily, from this post).

Three years ago, IIT-Bombay did a study concerning the Pedder Road flyover. The IIT team found that 60,000 cars use Pedder Road every day. Let's inflate that to 100,000 given the three years that have passed, and let's say all those cars use the BWSL. According to this report, each car carries an average of 1.75 people. In other words, cars on the Sealink are carrying 175,000 people a day.

Sound like a big number?

But how many trains pull into Churchgate? Assume they arrive within 4 minutes of each other on average. In an hour, that's 15 trains. (In a day, Western Railway alone runs 980 trains on its entire system, so 15 is actually an underestimate. Never mind). Each 12-car train is supposed to carry about 2200 people, though during rush hour, the load can reach 6000. (Figures extrapolated generously from 9-car train figures here). Let's take an average of 5000 per train in rush hour: that's 75,000 people arriving in Churchgate each hour. Broadly similar numbers for VT, so that's 150,000 people arriving downtown every hour.

What does the back of our envelope show? That in one hour during the morning rush hour, nearly as many people (150K) arrive in downtown Bombay by train than travel both ways (175K) by car on BWSL all day.

This does not take into account bus traffic, which will change this comparison substantially. But this point remains valid: far more commuters in Bombay travel by rail than by car. In fact, the Mumbai Metropolitan Region Development Authority estimates that 88 per cent of this city's commuters travel by trains and buses. Nobody from that 88 per cent is using the BWSL.

Look at all these figures: 2.5 million out of 15m; 150K/hr vs 175K/day; 88% percent of commuters not in cars -- look at them and at nothing else about the BWSL, and you still have to wonder. In what sense does this new bridge address the commuting headaches of Bombay's residents?

Maybe I'll take the bullock cart ...


Rahul Siddharthan said...

Some initial reports called the bridge an 8-lane bridge; the photos suggest it is a 4-lane bridge (2 lanes each way). I appreciate the difficulty and expense of building such a bridge, but a 4-lane road in a city like Mumbai is, surely asking for gridlock. Why didn't they make it at least a 6-lane bridge? The incremental cost couldn't have been that much higher. And then they could have allowed buses. Better still, they could have had a reserved lane for buses.

And of course, the entry and exit plans should have been better thought out, as you say.

Shortsightness, and pandering to car owners, everywhere...

MinCat said...

did you know bhikaji cama place in delhi has several no elephants signs, by whicvh i meant a round sign with an elephant in silhouette and that diagonal red no sign. i think i saw a no camels there once too.

Dilip D'Souza said...

Rahul, it is right now a 4-lane bridge (2 each way). From photos I've seen, and from some hints we got in the murk last night, I think they are building a parallel set of 4 lanes. Thus 4 each way. I hope one each way will be dedicated to buses.

Dilip D'Souza said...

MinCat, but why the fear of elephants at Bhikaji Cama place? Is it routinely overrun by pachyderms?

Suresh said...


The bias in our policy making towards "big" but relatively useless projects is by now, fairly well known. About 3-4 years back, I attended a talk in Chennai by the MIT economist Abhijit V. Banerjee who touched on this theme. He mentioned that there were a number of efficient low-cost solutions to many of our persistent but troubling problems. Malnutrition, for instance, could be addressed by adding nutrients to the cereals distributed via the PDS system. This could be done fairly easily. The problem, he went on to add, was that these low-cost solutions did not attract the attention of our politicians and bureaucrats because they were not "glamorous" enough. Indian politicians are of course not alone in preferring "glamour" but unfortunately our problems are far more daunting than those in many other countries.

What you say about the Sealink is consistent with what has happened elsewhere. A few years back, Mr. Arun Shourie made a big deal about how he had used his MP allowance to build a Centre for Biotechnology - or some such thing - in IIT, Kanpur. This was reported, I remember in the Indian Express. Without begrudging IIT Kanpur, one ought to have asked - but of course, no one did - whether this was an efficient use of public money, particularly in a state like Uttar Pradesh which has among the worst social indicators in the country. Mr. Shourie, unfortunately, is not alone here: This attitude runs across the political spectrum.

Abi said...

You get a swanky bridge, but buses are not allowed?

Even the ban on two-wheelers is difficult to understand, but a ban on buses -- when cities across the world are busy creating exclusive bus-only lanes -- is completely insane! I hope this bus-ban is only temporary.

km said...

Well, there clearly was the great Envelope Shortage of 2000-whenever.

I didn't know buses aren't allowed on the SeaLink. They could have at least turned this bridge as a 4-lane HOV link and encouraged car pooling.

Sumedha said...

About the first point in your post: I do agree. I love India, and it's signs that would be weird everywhere else, but are so normal here. :D

csm said...

one of the points never discussed is the cable stay design.
i was told by a civil engg friend that this technology is used in situations where the span has to be raised and lowered to accommodate sea faring traffic.
and i recall reading on the 'official' website that this tech has been adopted because of current sea faring traffic into the mahim bay.
am now unable to locate this detail online.
i feel that they could have done a simple vashi type bridge at 1/5th of the cost :-) but then how will the MPs and MLAs fund their next campaign ;-)

Azous D'Pilid said...

D'Souza, I am really beginning to wonder about you. Are you really as dumb as it seems? The reason buses are not plying on the bridge are because of some toll tax issue. It is not a permanent ban. You almost make me want to believe in God and plead with Him / Her / It to put a limit on the amount of stupidity permitted to a human being. Tell you what, why don't we impose a quota on the amount of stupidity excreted by you, and reserve the rest for Mayawati and Varun Gandhi? Or would you prefer a tax? I am sure HRH Raoul Maino can institute some legislation on your behalf.

Dilip D'Souza said...

Suresh, what can I say. What you say applies across the board, across the political spectrum.

csm, I don't recall the plans mentioning the need to raise the span for boat traffic. I don't think there are any boats that use the Mahim Bay that are tall enough to need such a span -- after all, this is the realm of small fishing craft, that's all. I think height above the water may be an issue if/when they build the link on the eastern side of the island, from Sewri to Uran.

Incidentally, having driven over it twice, I am always awed by this bridge, especially by how it addressed the issue of sea-going traffic.

Finally, it is also sad that the BWSL seems to have no place for pedestrians. One of the charms of the Brooklyn Bridge, for example, is that you can walk across, stopping every now and then to read plaques that tell you how it was built. Offers you a chance to sense and relive that history.

Just saying said...

A bridge built for cars, which also has a toll for its usage, one would think, frees up the regular roads for other commuters. While not costing the government in the long run, through toll collections.

Or, is there something I am missing.

Rahul Siddharthan said...

Dilip, well, who thinks of pedestrians around here?

I'm sure the majority of people who use the Brooklyn Bridge, or the Golden Gate bridge, are pedestrians. In the former case, many pedestrians are practical users (i.e., they actually walk across because they need to get to the other side, not because they're tourists enjoying the view). The BWSL is a bit too long for that, but it could have been a very enjoyable walk for those who wanted to.

You say they may be having plans of expanding to 8 lanes -- hopefully that includes potential pedestrian walkways. And bicycle paths too.

Dilip D'Souza said...

Rahul, about the possible 8 lanes, take a look at this photograph.

What's in use at present is the carriageway on the left, only.

(This photograph and more available here).

Rahul Siddharthan said...

Ah ok, that looks a bit better. Given the yellow dividers in each carriageway, one sincerely hopes that they will reserve the outermost lane for bicycles (ha, fat chance), the next lane for buses, and the inner two lanes only for cars. No room for pedestrians, of course...

Azous D'Pilid said...

'Just Saying' - it is not you who is missing anything...



For those who can read English, those links say that the bus issue is being negotiated, but note how D'Souza decides not to mention that anywhere, and simply says that buses are not allowed to ply.

In fact, if you look at the wikipedia article:


it says: "8 lanes of traffic with 2 lanes dedicated for buses."

BUSES. Can anybody read that? How deaf dumb and blind are the users of this site? Bunch of idiots.

Rahul Siddharthan said...

"Azous": thanks for the entertainment. Always nice to relax at the end of the day. The Wikipedia in particular is hilarious. I suspect you and your friends have been busy editing it.

Phoenix said...

Siddharthan, I had nothing to do with the Wikipedia. Don't blame me, got it?

Anonymous said...

>> "For those who can read English, those links say"

tried cliking those links. looked like tamil to me. could'nt read.

Azous D'Pilid said...

Rahul, you clueless moron, you can check the history page of every wikipedia article, along with the discussion section, in case you doubt the article's veracity.

Furthermore, again, I love your selective sight. You have nothing to say about the other 2 links.
But it is more fun to play chamcha to D'souza than to use your independent brain, isn't it?

Tamil D'Souza said...

Hey Anonymous,

Ennoda poola oombuda .

Is that enough Tamil for you?

Phoenix said...

My name is Tarun Pal. Used to blog as TTG. Got rid of my blog. Came back as Phoenix. With Another blog.

Now I get my kicks calling myself "Azous", "The Original Azous" and "Ot" and maybe more. You expect me to use my own name?? Come on, get real. You especially, you clueless moron Rahul. (You related to HRH Raoul?)

Rahul Siddharthan said...

Now I get my kicks calling myself [names...]

Erm... yes. It's quite obvious that you guys have no other ways to get your kicks.

Anonymous said...

>> "How deaf dumb and blind are the users of this site?"

you tell me. from your postings, your'e obviosly a frequent user of this site. how deaf dumb and blind are you??

csm said...

just to share the doubt I had raised on the cable stay design, I had asked this to my friend who questioned the design in the first place.

He and another civil engg friend have shared their thoughts on the design.

Just wanted to close the loop...

response 1
there is probably some element of over engineering. Bridges and high rise towers are as much about show of status/symbol/power as much as it is about utility value. why the race to having the highest tower in the world is still on with the bastion being handed over to asia from the west (europe and america) recently. longest span bridge and the most 'beautiful' bridges follow a similar pattern as well.

the choice of cable stayed bridge might be to showcase the status. there might be real engineering reasons that might justify it too like the ones kid listed. you'll probably find it hard to decisively prove one vs the other.


response 2

As far as I can remember, we were only speculating about why the sealink was a cable stayed bridge, I don't think I've read anything conclusive anywhere about why it should be so. There are 3 possible reasons for doing a cable stayed or suspension thing:

1. Keep the channel open for ocean-going traffic (like Golden Gate Bridge etc. where a pre-condition was that San Francisco and Oakland ports would have to be operational even after a bridge was built, so many piers wouldn't have been feasible)

2. Technically infeasible to put piers in the deepest portion of the channel, either because it's too deep, or the sea-bed isn't good enough in terms of support

3. Cost & time - Possibly faster and cheaper to have 1 (for cable-stayed) or 2 (for suspension) huge piers and hang the bridge deck off it, rather than 20 piers and support from below.

I don't have too many fundaes on any of this, cc-ing Kalyan who is rumored to have been a practicing structural engineer!