Can RAJAGIRIYA flyover ease the congestion along A000?


By Goyan Dias

Several readers have asked whether the Rajagiriya flyover will help ease traffic congestion along Kollupitiya-Sri Jayawardanapura road or the A000 road.


A flyover across a level crossing is acceptable as can be seen at Dematagoda on Baseline Road and Kelaniya on the A1 road. But, as for a flyover at grade intersection many things have to be factored in. In the first place, it will be only a temporary solution.

If long-term solutions like Light Rail Transit (LRT), Bus Rapid Transit (BRT) etc., have already been identified there are many alternative and economically viable temporary measures to ease congestion without permanent structures like the flyover at Rajagiriya. A flyover, steel or concrete has a design life exceeding 100 years.

I had the opportunity to participate at Asian Conference on Remote Sensing (ACRS) held in Colombo, 2016. There was a presentation on "An alternative measure to mitigate congestion along the Baseline Road through capacity augmentation of available links – A GIS based Approach". The main finding in the paper was that within a radius of 16-20 km from Battaramulla, there are enough roads, other than A and B, of which volume/capacity is still less than 0.3. This means you can reach Battaramulla without experiencing any sort of congestion simply by using appropriately selected local road network instead of conventionally using congested A or B class network.

One writer, Dr. Ratnasiri, being a resident of the local area had come out with a similar approach i. e. how to make use of available links with few improvements to ease the prevailing congestion at least to affordable levels. I request the RDA to map all links suggested by the writer and do a spatial analysis using GIS to trace out optimum links. Approaches of this nature are financially viable temporary measures, until long term remedies are adopted.

The 533 m-long Rajagiriya flyover, which is now nearing completion at a rate of Rs. 8.5 billion per km, is also supposed to last at least 100 years. At the same time, we have been made to understand that steps have been taken to have an LRT system connecting the Malabe with Kollupitiya and its trace will follow the existing center line of the A000 road. If so, how will the LRT go through the Rajagiriya junction? LRT certainly will be a long-term solution so the issue is who decided to have a temporary solution (a flyover) at a rate of Rs. 8.5 billion per kilometer? Further, urban planners have now realised that flyovers, in general, tend to promote private vehicle use particularly in respect of countries like ours, i. e., those who have kept away negotiating the Rajagiriya junction due to the prevailing congestion will return once the flyover is completed thus increasing the volume of traffic!


The Figure 01 shows a typical A Grade intersection with four approaches, of which the through movements of the main road have been separated with a flyover. Now, assume, during a working day peak time, total traffic volume both directions in vehicles per hour (VPH) at B-B is V2 at 715AM, without a flyover in place. The only difference the flyover could do is to have same V2 at the same place, this time not at 715AM, but a bit prior say by 712AM or by 713AM and thereafter V2 volume has to undergo the same agony as it did earlier with no flyover. Flyovers at Nugegoda and Dehhiwala, too, experience the same problem.

As regards the Rajagiriya junction, the through movement separator now nearing completion will lead to the same outcome as pointed out in the example above.

One obvious reason why the Rajagiriya flyover will not be effective is the heavy right turning volumes entering via by roads on to A000 just prior to the flyover and again just after its landing. This aspect has been correctly pointed out by several writers living within the vicinity of the Rajagiriya flyover. The issue is whether the feasibility study addressed these concerns. Under any circumstances the public has a right to know the conclusions of the feasibility study which may have recommended a flyover of this nature at Rajagiriya.


In fact, solutions to traffic congestion require a systematic approach. Congestion has spatial and temporal dimensions, i. e., no road is congested 24 hours a day and similarly no place on a road, too, can get congested throughout the day. An integrated system comprising both surface and rail modes certainly will be an effective solution.

The following are some alternatives we could consider to manage traffic congestion:

1. Making use of potential capacities of available links within a radius of 20 km from Rajagiriya,

2. Use of information technologies (i. e., use of intelligence Transport system tools) for the provision of spatial and temporal status of congestion to commuters,

3. Having a well thought national policy for spatial planning of urban land use,

4. Gradual introduction of flexi-working hours and promoting virtual working modes etc.,

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