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Poor design of flyovers lead us nowhere in solving traffic problems
Written By Vasanth - 29 October, 2009
Bangalore Design Complaint Transportation Infrastructure Flyovers and underpasses
All over Bangalore, there is a galore of small small flyovers and now underpasses. But, none of them are constructed with thorough thought process and planning behind it. Usual mode of construction of flyover is to have 4 exit ramps and 4 entry ramps in semicircles like we have seen in foreign countries as well as in our NICE Somapura road junction. It eliminates junction waits in all four directions in all possible 12 combinations.
Domlur Flyover...
In Bangalore, we have our own ways of construction such as one underpass and one flyover crossing in a + just addressing the straight moving traffic and not the turning traffic which serves 4 combinations. Good examples are the Dairy Circle, Jayadeva Flyover or sometimes flyover just addresses the only one straight moving traffic or 2 combinations like the Silkboard flyover which servess only the Hosur Road and not the Ring Road.
In a junction, there are 12 possible routes. Our flyovers or underpasses usually serve 2 - 4 possible routes only. Very rarely such as Domlur flyover which can address most of the combinations.Because of this poor design, irrespective of number of underpasses or flyovers, blockage continues to prevail in the junctions.
But, all 12 combination needs more space at the corners of bottleneck junction which is difficult to acquire in Bangalore.
Atleast, wherever possible, it could have been constructed to address maximum combinations, but it was not done. Example is Silkboard flyover, where plenty of space is available at the corners, but there is no ramp and serves only 2 combinations.
COMMENTS
Jayadeva - Silkboard on ORR, always slow moving
Vasanth - 30 October, 2009 - 13:06
Jayadeva to Silkboard, there is always slow moving traffic. Traffic signal in BTM junction leads to long jams same is the case in Devegowda Petrol Bunk. Long wait signals always causes delays, frustation builds and people try to release all their conserved energy during the wait once the signal turns Green.
Synchoronized signals is another necessity to remove the frustation and rushing. Something like an average travel at 40kph should lead to all signals showing green.
Here is an example of synchronized signal in Denver.
full cloverleaf to be avoided if possible
blrpraj - 30 October, 2009 - 16:54
The full cloverleaf interchange shown in the very first photo looks good from the air but is an outdated interchange design that is prone to accidents and traffic jams caused by weaving traffic. This design was essentially used to provide connectivity in all 4 directions between 2 different roads at a lower cost with minimum concrete. Also, one should not forget that land is a premium & a full clover leaf occupies more land than a multilevel stacked interchange.
I am not sure if that is the way to go for future interchanges in and around Bangallore. Just my 2 paise..experts please add if you have more knowledge; but yes, I concur with the author of the thread that more thought needs to be given to the design and implementation of flyovers.
blrpraj - 2 November, 2009 - 06:01
"why do you say the above? can you explain. alternates? thanks"
I say it precisely because of the "weaving" traffic that I mentioned. Having driven through one such interchange before, during and after reconfiguration I could see a noticeable difference (before ..when the interchange was a full cloverleaf and after..when it was reconfigured to a partial cloverleaf). The interchange I am talking about is the I-405 and SR 167 interchange in Renton, WA of US near Seattle.
Well, the alternates are to provide directe connections via flyovers. Such reconfigurations of full cloverleafs are going on in quite a few places in the US wherever possible. I had to google around quite a bit to come accross an article that explains the issue that I was referring to; this perhaps should explain clearly the flaws of a full cloverleaf and why the experts are getting away from it and what the alternatives could be -
Please note that I am not saying a full cloverleaf is bad because the US says so. Just driving through one made me question the design of the interchange (why was it designed in such a crazy way)..further analysis and digging around in libraries and a chat with civil engineers revealed that a full cloverleaf was the cheapest (and state of the art) way of providing full connecivity in all directions between 2 intersecting high speed roadways in those days (60s and before) when traffic was relatively low; not any more though with todays traffic volumes. Now, it does not of course mean that the traffic jams will disappear in a reconfigured interchange..it is just that the cloverleaf is the least efficient of interchanges for getting the job done.
To me it seems like our planners are going for the lowest cost solution by adopting outdated full cloverleafs.
blrsri - 30 October, 2009 - 10:31
very true that the junctions are the culprits for jams everywhere..
btw to solve the silkboard deadlock, which will get worse with the elevated highway being commissioned, we can have a bridge over the existing bridge..like how the Nice road and the BETL meet on hosur road..
this should solve the silkboard maha jam!
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