The sketch below illustrates what I described previously. The shoulders of the road/s may need some widening to allow for bus bays & barricades can be used to physically separate these bus bays from other (mixed) traffic.
The traffic light signals & the stop line have to be moved well before the street shoulders & bus stop/s at all four locations to allow for sufficient separation & improve pedestrian safety, particularly along Hosur road.
If buses have to turn right under the fly-over, they would have to wait at bus stops or slightly ahead & await a green signal (Traffic lights mounted on the ramp would be visible to buses at stops).
If they were to turn left, they would have the benefit of bypassing the traffic signal waiting (Other traffic might have to wait for a green if free left is not provided).
Along Hosur road, if buses are straight bound, they can be allowed to proceed straight at ground level (adjacent flyover ramp) in both directions when the traffic light is green for right turns only (they cannot obviously proceed when lights are green for both ways straight pass along ORR). All other traffic must however, be restrained from entering the bus-only straight tracks at ground level.
This arrangement provides for safe pedestrian crossing & bus interchanges without the need to walk long distances. It also offers some basic priority measures for bus & bus travelers.
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Needs more thinking
So I see two big new things thre.
Perhaps your thinking is - why make the buses wait at traffic light, and then again at the bus stop. Instead, place the bus stands just before the traffic lights itself.
I suspect that eleminating signals for vehicles going south towards E-city would be a design requirement from BDA. Any takes on that?
Also, you have not made use of some good space available under the existing flyover - those two blocks of 10-150 sq meter worh space could see some creative use.
Silkboard Jn - Clarifications
Generally, the choice for placement of bus stops at or closest to intersections is to facilitate commuters with easy access to it from any direction (ie. from any one of the four 'arms' of the junction). A second advantage is much easier interchanging of buses by commuters.
In this case, it would be better to have bus-stops at bays closest to the signals, or merge the signal stops for buses with bus-stops as shown in the sketch. This may also provide some priorities for buses & make it easier for commuters, by & large.
If bus bays are provided (as shown), taking a free left by buses can be made possible anytime, since it will not conflict with other traffic. However, since pedestrian crossings have to be provided under the flyover along Hosur road, free-lefts would have to be removed for all other (mixed) traffic, except buses.
There is still an element of danger in allowing free-left for buses since it might overlap with pedestrian crossings across Hosur rd, but with some measures (such as elevating pedestrian crossings, signage, etc.), this can still be made possible safely.
Headroom below the flyover will keep diminishing as one moves away from the junction + there will be more frequent pier obstructions. Hence, space below the flyover ramp is best utilized for pedestrian facilities. If bus stops are located below the ramp, it would be cumbersome for entry & exit of buses & would also have to be closest to the junction because of limited headroom further away. Also, there is the danger of conflicts between buses exiting out of such bus-stops & moving vehicles on adjacent lanes.
If signal delays have to be eliminated along Hosur rd, the only option is for buses to go over the ramp, but this would mean retaining bus-stops before commencement of the ramp on each side, which would mean longer walks for commuters bound for destinations on three of the four 'arms' & also for interchanging buses.
More grade separation (such as buses only underpasses) may not be possible due to the existence of large SWDs :
1) Along ORR on southern edge.
2) Along Hosur rd on western edge.
Silkboard redesign - Difficult without information
The broad principles are clear and agreed upon - we want good pedesrian/bus interchange facilities and suffficient capacity to meet demand, especially the peak demand.. The flyover section along Hosur road, as SB pointed out is not a problem. The rest of it is a mess already today... will be worse when the upgrades come.
So the questions that need answers are: (a) What is the current capacity of this intersection - ideal vs actual (b) What sort of traffic flow is expected from/to various directions (c) Is the BRTS implemented at the Agara and Iblur intersections going to extend all the way here? Is it physically possible to solve the problem by just improving this intersection or would alternate means of Hosur road access have to be worked out.
Without this basic information and some expertise to handle it, we will only come up with marginal improvements. So how do we go about this? Right now, I am not sure.
Humble Suggestion
Friends,
While all you worthies are brainstorming about the design of the Silk Board junction, may I humbly suggest any remodelling should, if possible take into account the autobahn principle of "levitating" the roads to ensure it lasts for ever and ever?
Similarly, pedestrian walkways too should, if possible be demarcated by a green patch of luscious grass rather than merely painted areas.
Just my two paise worth.
RKC
RKC
"Fire-Fighting" - As Usual
Sanjayv - You've raised many good, pertinent questions. As of now, measures being taken are merely to deal with day-to-day problems. Long-term solutions are not being addressed, yet (except for Metro-rail). Thus, the authorities are "fire-fighting" all the time :
(a) What is the current capacity of this intersection - ideal vs actual
Normal 0
I have not come across any recommendations for intersections, but the following has been quoted for roads as ideal (CTTP-2007, table 3.16) :
Normal 0
2 Lane, Undivided, One-way - 3600 PCUs per Hour
2 Lane, Undivided, Two-way - 1800 PCUs per Hour
4 Lane, Undivided, One-way - 5800 PCUs per Hour
4 Lane, Divided - 3600 PCUs per Hour
6 Lane, Divided - 3600 PCUs per Hour
6 Lane, Undivided, One-way - 7000 PCUs per Hour
The 12 hour traffic volume along Hosur rd has been quoted as 66, 116 PCUs (CTTP-2007, table 3.1).Thus, average traffic during the day is already in excess of 5500 PCUs per hour, which is well over the recommended capacity (3600 PCUs per hour). In peak hours, it is likely that traffic is already over double the recommended capacity (ie. >7200 PCUs per hour).
No data has been quoted for ORR at this location, but I suspect that this is also well over the limit.
(b) What sort of traffic flow is expected from/to various directions
There are projections & forecasts in the study report, but actual figures have not been quoted.
(c) Is the BRTS implemented at the Agara and Iblur intersections going to extend all the way here? Is it physically possible to solve the problem by just improving this intersection or would alternate means of Hosur road access have to be worked out.
About BRTS - there has been no announcement yet (I have not come across any such report). Provisions are being made at new flyovers such as Agara & Iblur to take care of this, in case BRTS is planned later, that's it.