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Minority Biased Junctions

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Written By rajatbhatla - 29 August, 2007

Traffic Bangalore Infrastructure Junctions

About 4 years ago, Bangalore got its spanking new 200 ft wide double laned with 40 feet service lanes, Outer Ring road...

One would drive up here to break free from the traffic snarls elsewhere in the city...and check if their spanky investments still worked at high speeds.

Mostly worked fine, until a small hitch started showing up first little, then some more... and these days in full measure...

The hitch is what I call "minority-biased-junctions"... Bangalore's archaic mechanism of junction management...let me explain..

1) There is a very wide road, which is the highway, and contributes 80-90% of the traffic of the junction

2) The perpendicular "feeder" road is more like a 30-40 ft wide street, basically an outlet for the settlements off the highway, and contributes 10-15% traffic of the junction

3) There are no traffic lights (if they are a fair chance they will not work)

4) The "minority bias" is a speed breaker, placed not on this "feeder road" but on only on the highway in both directions.

6) What happens as illustrated above is that while the 70-80 Km/h highway traffic slows to a halt, the "feeder" traffic from the jumps on the highway as there are no deterrents, human, electronic or physical to it...

7)...and the 80:20 rule plays out...20% of traffic gets 80% of the junction time and 80% gets 20% of it...

Perhaps the idea was the same socialist one - tax the big road folks to feed the smaller road folks..problem is, it works about as much as socialism did for us.

In peak hours, you have a mile of traffic build up on this 200 ft wide highway, while the 30 ft wide street traffic jumps right on the road, nearly no waiting ...

This problem is not new, it got worse on the Hosur Road before we got lucky with a 9 KM elevated road ...so no junctions possible... but unlikely we'll get as lucky again...

So please, planners can you try wake up to some simpler solutions like simple signals adjusted to the traffic flow and do away with these "minority-bias" speed breakers!

 

(Originally posted at my personal blog here)

COMMENTS

was not like this

thampan - 30 August, 2007 - 05:13

The scenario you explained was not like this earlier. The village traffic did not account to 20%. It was a meager 1%. After the road came into being, people started to realise the potential of the area. cheap land, vast land, big road. Hence buildings started coming up on either side of the road, Now you can see scores of IT companies on either side of the road, and 100s of apartments. And apartments started coming up on all these village roads which you mentioned. The only route for the people (floating/fixed) to travel is to get on to the ORR at these junctions. I doubt whether the BDA does has any norms on the number of vehicles which will come on to the main roads as a result of the new buildings. Hence the traffic volume has increased at least a 100 times on the ORR. Solution -------- Construct access ways to the service lanes from the main roads. You can build underpasses/fly overs so that the junctions are not choked. Recover the cost ( at least partially) from the builders. when permitting a building, consider the increase in traffic which the building will cause and have adequate measures in place to handle that. (another example, traffic jams near forum/big bazaar)

ORR

tsubba - 30 August, 2007 - 11:39

rajat cool illustration man. though i'll side step the mine. BETL road has too few exits and entries IMO. access ways to service lanes aha! what do you mean by that? can you elaborate on that? they are now retrofitting gradeseparators on many of these junctions.

access ways

thampan - 31 August, 2007 - 05:04

Have mini flyovers/underpasses at these junctions such that the vehicles which are crossing the road does not interrupt the main traffic. We dont need octopus flyovers as the only purpose is to prevent the traffic from the side roads interupting the main traffic. So it can even be a bridge across the ORR with signals on top which will regulate the flow of traffic to the sides. The vehicles can enter the service roads from the service lanes. current roads ================= ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ---------------........................--------------- ............................................ ............................................ ---------------|............||.........------------- ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| Proposed road ================ ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|...|............||.........|...| ...........|.|v|........^...||..V......|v|.| ...........|.|v|........^...||..V......|v|.| ...........|.|v|........^...||..V......|v|.| ------------ ________________________--------------- ................>>>>......O......<<< vehicle movemement shown by arrows ( roughly)

Help Understand

tsubba - 30 August, 2007 - 12:59

thampan how to read this. can you draw these? cading is a pain. perhaps on a napkin and then post a pic mebbe? i understand what you are saying, about bridges, i was also thinking along the same lines. (convert ORR to an access controlled road, 60 kms about 25-30 exits, fly over the rest of the intersections but connect them to exits through service roads.) but am not clear about how to connect through service roads, i think this is what you are describing in those images. can you describe sme of the general characteristics of ORR.

how many?

tsubba - 31 August, 2007 - 05:43

all junctions all along the 62 kms of ORR? How many are there? if you decide to build a grade separator at a particular intersection then I understand the design. but if you build only 25-30 GS exits, then how to connect the remaining roads to ORR through these GS exits using service roads i donot know.

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