From Roundabouts to Flyovers:
The way out of traffic congestion is not Roadway but Railway!
“In a move to ease the traffic congestion, the Government will construct 16 flyovers and interchanges in the main cities in Colombo and suburbs shortly”, said a report in the Daily News about a recent government announcement.
The report went on to say that the cabinet had approved the appointment of a feasibility and procurement committee for this ‘mega road development project.’ The report lists 12 flyovers and 4 interchanges at the following locations:
1) Colombo – Kandy Road (Kelaniya)
2) Veyangoda – Nittambuwa – Ruwanwella Road and Rail grade separation (Veyangoda)
3) Colombo – Horana Road (Kohwela)
4) Colombo – Horana Road (Borelesgamuwa)
5) High Level Road / Stafford Avenue (Kirulapona)
6) Galle Road (Dehiwela)
7) Baseline Road / Edmonton Road
8 ) Slave Island (near Beira Lake)
9) Kanatte Junction (Borella)
10) Chatham Street / Hilton Roundabout
11) Galle Road / Station Road (Bambalapitiya)
12) D.S. Senanyake Junction (Borella)
Interchanges: Four interchanges are planned at Welikada, Orugoawatte, Panchikawatte and the Lipton Circle.
Road / Rail Flyover or Grade-separation
Of the 12 proposed flyovers, only the one in Veyangoda involves a road/rail grade separation and is located out of Colombo. All the others involve road/road grade separations and are in Colombo and adjacent areas.
Road/Rail grade separations especially in the Colombo, Gampaha and Kurunagela Districts are long overdue and deserve the highest priority as the existing (at-grade) rail crossings in these areas have become virtual death traps.
As a rule of thumb, the accident rate at road/rail crossings increases rapidly after the cross-product of the daily roadway traffic volumes and the number of trains per day exceeds a certain threshold. Priority should be given to locations that show the highest cross-products.
Accordingly, the Veyangoda road/rail flyover should be given the highest priority, while each of the remaining 15 road/road improvements should be subjected to a rigorous review in regard to costs and benefits before the final decision to go ahead is made.
Road / Road Flyovers and Interchanges
Road/Road grade separations can be limited to flyovers (one road ‘flying over’ the other, with no connection between the two) or include interchanges (flyover with ramp connections between the separated roads). The sole purpose of flyovers and interchanges is to allow traffic on crossing roads move uninterruptedly.
At normal cross-road junctions, opposing traffic flows are controlled by traffic lights, or accommodated through roundabouts, or a combination of both. At significantly high traffic volumes, these measures fail leading to traffic congestion. Interchanges can accommodate much higher traffic volumes than signals and roundabouts but over time they too get clogged up with increasing traffic.
Expressways generally ‘fly over’ cross-roads or connected to them through interchanges. However, in building expressways it would be economical to include interchanges only at junctions where they are currently or immediately warranted by high volumes of traffic. At other junctions where traffic flows are lower, it would be economical to provide large roundabouts at the beginning and upgrade them later to interchanges as traffic increases.
Such a ‘staging’ (that is, building different improvements over a period of time) of flyovers and interchanges could be adopted in constructing the five new expressways identified sometime ago by the Road Development Authority.
Four of them will connect Colombo to Hambatota, Katunayake (Airport), Kandy and Anuradhapura. The fifth one is intended as a ring road around the Colombo Metropolitan Area. Of these, the Southern Expressway (Colombo-Hambatota) is currently under construction.
The eleven road/road flyovers and four interchanges listed above are not part of the proposed five new expressways. They are intended for existing trunk roads in mature and built up urban areas in and around Colombo. Their purpose is to alleviate the traffic problems at these locations.
Expanding road capacities including flyovers and interchanges to solve traffic problems in urban areas is at best a short-term solution. At worst and before long these improvements will only aggravate traffic problems rather than alleviating them. Furthermore, building flyovers and interchanges in mature urban areas can be sticky business because of their impacts on adjacent properties and disruptions they cause to long established patterns of mobility and interactions at these locations.
Imagine installing massive concrete conveyor-belts at the Lipton Circle and the impacts they will have on adjacent properties and institutions and the thousands of people who go there everyday – by walking, bus, auto, or car. Similarly, flyovers at Kanatte or Chatham Street will give a short-term advantage to cars and create concrete jungles for people. Impacts of flyover/interchange at some of the other proposed locations may be less severe and could yield some benefits. But each location in an urban area deserves special attention and the decision to build an interchange or flyover should not be taken lightly.
Rather than an expensive and disruptive grade-separation, a cheaper and more urban friendly option at most of these locations could be along the lines of the treatment now in place at the Maradana Road/ Panchikawatta/ Darley Road complex.
Colombo’s Transport Problems
The real problem with implementing flyovers/interchanges in urban areas is that they are incapable of addressing the problems they are meant to solve. This arises from three stubborn but simple facts.
The first is that in Colombo about 75% of the road space is taken up by private vehicles although they carry only 25% of the total number of people who are travelling during peak periods. So building flyovers and interchanges will ease the problem for only the 25% in cars but not for the 75% who are mostly in buses.
Second, although in theory enhancing road capacity should also benefit the buses, in practice it rarely happens unless capacity improvements are undertaken at pinch points where buses will benefit and buses are given priority movement over private vehicles at these locations. There is no indication that giving buses priority will be a factor in implementing the proposed improvements in Colombo. As well, the existing bus system is not set up to attract people who are not using buses now to use buses in the future. That will leave the current 75%/25% road disparity well intact.
Third, if the annual increases in car imports and usage continue as they are now, it will not be long before the new flyovers and interchanges are also clogged up. So we will be back with the traffic problem after huge expenditures and enormous disruptions.
For all these reasons and more, the solution to urban transport problems does not lie in roadway expansion or building flyovers and interchanges in densely developed locations. The solution lies in public transport – that will include a combination of a well-run bus system, an improved train service, and a mass rapid transit system in the long-term.
Sri Lanka needs its flyovers and interchanges – but more on the five Expressways identified by the RDA and less on the trunk roads inside Colombo.
It is instructive to look at what India has been doing in recent years to build both a gigantic expressway system to connect its major urban conglomerations – Delhi, Mumbai, Chennai and Kolkata, and separate rapid transit systems within each of these cities to address their internal (urban) transport demands.
The nearly 6,000 km long Golden Quadrilateral of national highways linking the four major cities and complete with all the modern freeway features is virtually finished on schedule.
A good portion of the project funding came from the extra rupee levied on every litre of petrol or diesel consumed since 1998. Supplementary financing came from the World Bank and other financial institutions. Indian companies worked alone and in joint ventures with Malaysian, Japanese and Thai firms to complete the whole project in several contract segments. Sri Lanka has a good neighbourly example to follow in building its own modern highway system to connect all of its Provincial capitals.
What is needed in Colombo, however, is what India is doing in each of its major cities, but at a reduced scope and scale to suit Colombo’s specific needs and priorities. Delhi is well on its way to completing the Delhi Metro Railway system comparable to the London Underground and the Singapore MRT. The Central government and the Karnataka State government recently announced the go ahead for a similar Metro system for Bangalore to be completed by 2011. A superhighway linking Bangalore and Mysore is already under construction.
In nearby Chennai, the debate is about extending the existing Metro (surface rail) system through a new Monorail system or a Bus Rapid Transit (BRT) system. Hyderabad is also reported to be evaluating the Monorail vs BRT system. A number of Chinese cities have successfully implemented BRT systems.
The point to make here is that to address urban transport challenges one has to look not towards flyovers and interchanges but for different public transit options – bus, rail, monorail, metro. Eventually a combination of all transit modes will have to be deployed. Colombo has to start from where it is now – revamping its bus and rail systems, working towards a Bus Rapid Transit System, and planning for a Metro (Mass Rapid Transit system) in the long run. Flyovers and interchanges are short-term palliatives, but long-term migraines.
By Rajan Philips
Source: Sunday Observer