Flyover Project In Colombo City Construction Essay

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A efficient transport network is the backbone of a healthy economy. As SriLankans most of our productivity is lost due to the inefficient and congested road network. One of the recent additions for traffic management and to alleviate congestion in colombo city and its suburbs has been the introduction of flyovers at important intersections of the main road corridors. The main function of a flyover is the separation of conflicting traffic movements thereby minimizing conflicts by using the vertical space. Therefore, it is assumed to cause less impact to the adjacent properties and the existing infrastructure. However, this depends on the type of flyover and the traffic pattern at the junction.

2. The efficiency of the recently introduced flyovers in the suburbs of the city of colombo can be tested by comparing before and after conditions of important traffic engineering parameters. It is also important to analyze the congestion level at the intersection and its significance compared to the entire road system. Basically the speed and the system capacity can be compared as main considerations to test this at a particular location. Moreover, the benefits and cost of a flyover against other reasonable and alternatives to obtain a similar result should be taken in to consideration and evaluated. In this research has attempted to compare the economic benefits of introducing flyovers against other short term and long term alternatives. The possible solutions available both from traffic and transport aspects are also widely discussed in my research.

3. The first of the series of large scale flyovers introduced to Sri Lanka recently are located across main railway lines in and around colombo. The first of these was a concrete cantilever type flyover in Ragama. This was constructed in 1996 in order to avoid the delay caused by the railway gate closures at the main line. A second flyover was completed along the baseline Road area.

Dematagoda which was also across the main railway line in year 2000 to prevent the stagnation of vehicles on the Base line road. This was a 6 lane viaduct (culvert) type concrete structure. The 3rd flyover, which is a steel structure, was constructed in 2008 at Kelaniya within a record period of just 66 days; this was also to avoid the delay from the main railway line across the colombo-Kandy Road. The main purpose for the construction of all these flyovers was to reduce delays caused to vehicle traffic due to the closures of rail gates and reduction of accidents.

4. The latest flyover was constructed at Nugegoda junction in 2009. This is the first flyover at a road intersection, constructed in order to reduce intersection delays in Nugegoda. This too is a steel structure.

5. From the above details we could basically divide flyovers in SriLanka in to two main categories,

a. Those across railway lines (railway overpasses) and

b. those across road intersections resulting in grade separations.

6. The comparisons of key performance factors such as speed, safety, and economic cost with or without the flyover can be analyzed for both categories. Also, the economic viability of each category could be tested by comparing the cost and the benefits of the design life of each flyover. Selection of the type of flyover and its design are also of interest. In this respect, the comparison between cost, life time, possibility of land use, space utilization as well as the visual and function impacts on the area would be considered as being relevant decision making parameters for the selection of the type of flyover.




The aim of this research is to identify and analyze the issues related the construction of flyovers at the traffic jammed areas in colombo district, How to improve & finds the achievements and drawbacks being available in the flyovers.


2. The growth of population, economy and as a result of the prevailing economic policy, the number of motor transport is increasing daily but the road network has not developed in such a manner to cater for the increasing requirement creating a great impact on the growth of our economy. Similarly the inefficiency of public passenger transportation combines together with this, as it is the mode of travel used by the general public for day to day activities.

3. Moreover Improvements to Public Transportation can reduce traffic congestion by attracting car and other motorized users to bus and train transportation hence can contribute to the economy in long term by reduce fuel consumption, efficient use of road and vehicle fleet, reduced accidents, etc. Increasing of private motorized vehicles by widening and improving more capacity to it will create further problems to the traffic environment in future. Hence, the concern of more tax and quota system to reduce vehicle ownership will help to reduce the vehicle growth rate. But at the same time government should improve public transportation to satisfactorily for the convenience of all users.

4. On the other hand very expensive infrastructure will negatively impact to the economy of a country as they lose the power for expenditure to other important needs at the same time hence the inflation rate would be unbearable if they are already have economic crisis. Therefore, injection of local funding to huge infrastructure which will produce marginal benefits is a waste for a nation. However, the flyovers also can be constructed using reinforced concrete structures too at lower cost than steel structure presented at placed in Colombo these days.


5. It is hypothesized that construction of flyovers at the traffic jammed areas as this is the best remedy for the issue, in this context there is no such requirement for add more kilometers to our road network.


6. This research paper examines the lapses in the road network, one of the most recent traffic management methods, Improvements to Public Transportation can reduce traffic congestion and public passenger transportation at present, on its maintenance and existence, and how it affects the economy of our country and the ways available to overcome the problem effectively.


7. The data for the research is collected both from primary and secondary sources.

Primary data

The Primary data has been collected from 40 samples in colombo district.

Secondary data

The data required for the research collected from the secondary sources with relevant Books, RDA/UDA Specialized personals and the Internet utilized.


8. My Limitation is

Primary data was collected mainly from questionnaires, it is assumed in the information is 100% correct.

Forty consumer of flyover were selected for the study. This also is a limitation in the generalization of the result.


9. This research paper is structured as follows.

a. Chapter 1 This is the introductory part of the research paper and it consists of general background of the selected topic.

b. Chapter 2 Methodology


Statement of the problem

The research hypothesis

Scope of the research

Method of data collection

Limitation of the research

The structure of the thesis

c. Chapter 3. This chapter studies current situation of flyovers srilanka.

Analysis the current situation of flyovers in srilanka

Global experiences with flyovers

Study area

Data collection


Flyovers at Road Intersection

New flyovers planned but lack proper pedestrian walkways.

Transportable Roadwork Traffic Signal System

Flyover Construction

d. Chapter 4. This part provides a Major issues and difficulties uplifting existing road network.

f. Chapter 5. This part provides a descriptive analysis of data obtained through questionnaire.

g. Chapter 6. This part covers the conclusion inclusive with list of recommendations.




1. Flyovers have been assumed to be an ultimate solution for traffic congestion in the congested cities of developing countries. Large number of flyovers has been constructed in our country in last few years. However, the actual performance of such flyovers is debatable when considering the overall impact to other transport functions such as pedestrian facilities, visual aesthetics and business developments in the locality. There is a strong public perception that flyovers have solved or will solve traffic problems in metropolitan areas.  Therefore, there is no apparent resistance from the public, media, politicians and administrators when flyovers are constructed.  The only resistance comes from the few that are adversely affected, for example, owners/tenants of business establishments, residents and civil institutions.  In response they are often criticized for not being socially conscientious and for being anti-development since they usually cannot justify their own reasons from a professional point of view and there is no support for them even if hundreds of thousands may even suffer from the adverse effects of such developments.  The position that the interests and convenience of society at large over the inconvenience or losses to a few are often ignored in many countries.  There appears to be no counter to such arguments since there is indeed some logic and truth to it.

2. It has in fact been shown that the convenience of a flyover mainly occurs only during the non-peak hours of traffic flow.  For example, during non-peak hours well-designed at-grade intersections like those in all present flyovers are doing fine as it is only in peak hours that flyovers have a slight advantage. The convenience is also felt only in 2 directions of traffic flow out of a possible 12 directions at an intersection.  These misconceptions have had a great influence on the public's mind that flyovers indeed solve

all traffic problems at intersections.  Only in-depth analysis and engineering computations can counter this influence. For example, our country and in developing countries are examining possibilities of introducing toll systems to recover the huge cost of these flyovers. However there are difficulties in implementing such methods due to the lack of space for toll booths and also the difficulty of imposing this to the users who only have marginal benefits from a single facility within the overall road infrastructure.

3. The experience of our country and in developing countries is that flyovers have not given the anticipated benefits for developing cities. Moreover this has been considered as a threat to the urban architecture as well as the accessibility within the city. Common complaints regarding flyovers are the negligence of public transport, transit facilities, and pedestrian facilities.


4. In the colombo suburban area there are four flyovers of recent origin. The three (04) railway flyovers namely at Dematagoda, Ragama, Dehiwala and the recently constructed at Pattiya Junction in Kiribathgoda are included in this study Figure 01. The Nugegoda flyover is at a road intersection. This too is included to be discussed separately.

Figure 01: Locations of Flyovers in Srilanka


5. The data for the research is collected both from primary and secondary sources.

Primary data

The Primary data has been collected from 40 samples in colombo district.

Secondary data

The data required for the research collected from the secondary sources with relevant Books, RDA/UDA Specialized personnel and the Internet utilized.


6. The analysis is carried out under two categories namely flyover performance at road intersection and flyover across the railway lines.


7. The travel time data of all the turnings including the through traffic on the flyover at Nugegoda intersection were used to calculate the average (daily average) speed and delay at each approach of road links (Figure 02).

Figure 02: Travel Time Survey at Nugegoda Intersection with Flyover

8. The average two way traffic flow speed on each 100 meters segment of all four road approaches (up to 2km) of the Nugegoda flyover. The average speed of road links other than on the flyover includes the signal delay too.

9. It was observed from the above analysis that flyovers at railway crossings give higher benefits when compared to that of road intersections. The comparison of basic values indicates that concrete flyovers are better than that of steel structures. This is evident when the life time and the maintenance of the two types of flyovers are compared. Even though the economic analysis was done for 20 years, the concrete structures can last for more than 50 years without many repairs on it. Therefore the benefits of concrete structures are much more than those indicated in this analysis.

10. The flyover at Nugegoda intersection designed for 20 years. According to the travel time survey data, this flyover indicates the lowest savings. It also has the highest per lane km cost. However, the signalization with improvements to approach links of the intersection as an alternative to the flyover indicates very well.

11. It was observed that the flyover or signalization alone does not solve the traffic congestion at an intersection but that it also needs capacity improvements of approach links for an improvement at that intersection. It can be observed that most of the intersection approaches are often blocked by parked vehicles and other activities such as uncontrolled pedestrian movements and temporary businesses on the walkways. Therefore it is often seen that the existing road infrastructures in urban areas are not properly utilized. The capacity of road links and the intersection can be improved by enhanced traffic management strategies.


12. It has come into the notice of the Srilanka that in order to improve the transport system the Srilanka government has planned plenty of routines. Integrated multimodal transport system, will play a prominent part in offering an effective public transport service and hopefully will reduce private vehicles.

13. All in all, the main focus is on the development of more roads and more effective mass transportation. Though, there is no emphasis on the common man- the pedestrian- and his requirement for safe problem free movement space.

14. There is no doubt in my mind that with steady increase in the numbers of cars and footpaths, pedestrian space in the colombo city has become increasingly marginalized. In other word, the footpath was meant to be a place for the common man to walk upon and did not belong to the owner of plots adjoining the access road.

15. Theoretically speaking, roads have been widened in Srilanka and flyovers have been built in all the major cities of the country without offering safe and convenient facilities for pedestrian to cross over. The requirement for adequate pedestrian space is an absolute must especially in places where large number of people gets together such as in neighborhood markets and shopping centers specially Dehiwala.

16. Unfortunately, here also, the focus seems to be on providing for the movement of vehicles and the parking of cars. Shoppers dodge their way around moving cars, three-wheelers, motorcycles and accidents are frequent and common. Despite this traders have continued to resist the pedestrianisation of shopping streets fearing loss of business.



Low-cost traffic signal system for one-way alternating traffic.

Easy to control, clearly organized at a glance.

Universal in use with power cable, Telephone cable and others.

All signal heads uniformity and simple.


Automatic fixed time mode

Automatic green time extension

Automatic green on demand

All-red in cable and radio mode

Manual operation from every signal head possible in cable and radio mode


17. Recent traffic counts have shown that there are in excess of 30,000 vehicles using the roundabout daily at colombo area. The straight-through movement between the east and west sides off the South Ring Road was the highest recorded traffic movement at the roundabout and represents approximately 40% of the total traffic using the roundabout. There was an urgent need for grade separation.

18. Effective traffic management throughout the duration of the project was vital as the same volume of vehicles used the roundabout during construction as they did before construction. From public opinion, traffic management was put in place effectively and major delays were rare.





1. Congestion can be reduced by either increasing road capacity (supply), or by reducing traffic (demand). Capacity can be increased in a number of ways, but needs to take account of hidden demands otherwise it may be used more strongly than anticipated. Critics of the approach of adding capacity have compared it to inducing demand that did not exist before. Reducing road capacity has in turn been attacked as removing free choice as well as increasing travel costs and times.


Adding more capacity at bottlenecks (such as by adding more lanes at the expense of parking/harden type shoulders or safety zones, or by removing local obstacles like bridge supports and widening tunnels)

Adding more capacity over the whole of a route (generally by adding more lanes)

Creating new routes

Traffic management improvements


Vehicle parking or non parking restrictions.

Vehicle park or no parking (Ride) facilities allowing parking at a distance and allowing continuation by private and commercial transport or selected lane.

Reduction of road capacity to force traffic onto other ways and modes.

Road entering fees (Southern highway) charging money for access onto a road/specific area at certain times, congestion levels or for certain road users.

Road reserve area, where regulatory restrictions prevent certain types of vehicles from driving under certain circumstances or in certain areas.

Rule/Policy approaches, which usually attempt to provide either strategic alternatives or which encourage greater usage of existing alternatives through promotion, subsidies or restrictions.


2. Global positioning system (GPS) devices are used to determine global locations points, which are measured and recorded as Longitude (E), Latitude (S), and Elevation/Altitude (meters above sea level). Anyway before commencement of a GPS survey must be required checklist.

Traffic monitoring, via radio, GPS or possibly mobile type phones, to advise road users.

Fluctuate type message installed along the roadway, to advise road users.

Navigation or clear identifying system possibly linked up to automatic traffic reporting.

Traffic monitoring / analyzing permanently installed, to provide real-time traffic counts.

Road traffic monitoring/Analysis, to provide information on highway.

Computerized highway system, a future idea which could reduce the safe interval between cars (required for braking in emergencies) and increase highway capacity by as much as 100% while increasing travel speeds.

Parking area and guidance with information systems providing dynamic advice to motorists about free parking.

Active vehicle controlling (Critical situation) system hard area (Parking, bus halt) as an extra traffic lane, it uses CCTV and monitor the traffic's use of the extra lane.


3. Other associated are,

School time (Start/End) arranged to avoid busy time traffic.

Driving behavior promotion and enforcement moreover driving practices, frequent lane such as security or school hrs etc changes can reduce a road's capacity and exacerbate jams.

Visual/Sound barriers such as horn CGR gate bell ringing etc; to prevent drivers from slowing down out of curiosity.

Condition of speed reductions, showing speed limit, humps etc with lower speeds allowing cars to drive closer together, this increases the capacity of a road.

4. Moreover where space-efficient vehicles, usually motor bike, three-wheels and cars ride or drive in the allocated space between cars, buses, and trucks specially peek hrs. This is however illegal in many countries as it is perceived as a safety risk.


Acceptable and accepted - only rail borne modes can in practice get people out of cars.

Smooth - no violent movements vertically, laterally, or backwards/forwards.


Re-assuring - tram lines (New proposal year 2009 but not succeeded) give confidence that service operates.

Safe - many times safer than vehicle travel.

Speedy - short journey times can be achieve.

Compatible with pedestrians in pedestrianised areas.

Clean and green - enhances the environment - no emissions at street level.

Avoids traffic congestion - through segregation and priority.

5. Roads including highways with grade separation generally allow traffic to move freely, with fewer interruptions, and at higher overall speeds; this is why speed limits are typically higher for grade-separated roads. In addition, less conflict between traffic movements reduces the capacity for accidents. Motorways, though having higher average speeds, usually have much lower accident rates per distance traveled than roads which are not grade separated.

6. However, grade-separated junctions are very space-intensive, complicated, and costly, due to the need for large physical structures such as tunnels, ramps, and bridges. Their height can be obtrusive, and this, combined with the large traffic volumes that grade-separated roads attract, tends to make them unpopular to nearby landowners and residents. New grade-separated road plans can receive significant opposition from local groups for these reasons.

7. Rail-over-rail grade separations take up less space than road grade separations, because shoulders are not needed, there are generally fewer branches and side road connections to accommodate (because a partial grade separation will accomplish more improvement than for a road), and because at-grade railway connections often take up significant space on their own. However, they require significant engineering effort, and are very expensive and time-consuming to construct.

8. Rail-over-road grade separations require very little additional space because no connections need be built, but require significant engineering effort and are expensive and time-consuming to construct above.

9. Many closures from 1990 to 2010 happened, and many people thought that it was the beginning of the Colombo, Galle, Kandy vehicles, but the situation changed after 1990. Large number of automobiles started creating pollution and smog. High rising of petrol & diesel in international market also thought people that petrol running automobile is far worse than electricity driven street rail.


10. Under this topic road infrastructure can be improve under this conditions,

Grade or type separation, using bridges (or, less often, tunnels) freeing movements from having to stop for other crossing movements.

congested motorway-type roadway.

Reducing junctions

(1) Providing through lanes that bypass junction on-ramp and off-ramp zones (Except highway access)

(2) A grade access road, roads that limit the type and amounts of way along their lengths.


11. Considering the day today, certain sections of highway operate in the opposite direction on different times of the day or days of the week.


12. Separate lanes for specific user groups,

Public bus ways,

Pedestrians (High occupancy vehicle lane)


13. Urban planning and city planning (UDA/NHDA planning) practices can have a huge impact on levels of future traffic congestion, though they are of limited relevance for short-term change.

Grid type plan (Interconnect system) including road network geometry, rather than tree-like system which reduce local traffic, but increase total distances driven and discourage walking by reducing connectivity.

Zoning laws that encourage development under mixed type, which reduces distances between residential, commercial, and recreational destinations (and encourage cycling and walking)

The development is residential and commercial areas designed to maximize access to public transport.


14. A well-developed transportation system plays a great role for any country of the world to develop and it remains so for our country also. The country has developed up to a certain extent throughout the time but the transportation has not, to cater for the increasing demand. On our journey for development this has to be the primary area to be considered. It is not only a responsibility of the government but also depends on the attitude of the people. The government also has the responsibility to put a genuine effort for this other than going only for political achievements and thereby should give priority for the development of this area.

15. When I made the interview RDA and UDA expertise they are said that "we have done researches and given most economical and the feasible methods to develop this area but we don't know how it is going to be done due to non availability of funds and facilities"

16. The above economic analysis is carried out considering only the volume of transport savings based on a travel time survey at each flyover location. A comprehensive study could have been carried out to test the situation more accurately if the respective data sources had been available.

17. However, this is a good strategy for eliminating the delay at railway crossings as a long term consideration. Also the concrete flyovers across railways are more economical than the steel bridges constructed in a very short period.



1. My Analysis was done in the area of Nugegoda, one of the closest towns to the Colombo city. Questionnaire was prepared and distributed among all age groups. The sample size is 40 personnel and all responded with their identity.

Figure 01

2. My 2nd observation was made to find out how many people (from 40 personnel sample) are using flyovers and how often they use it. According to Figure 02 it has been observed that more than 65% persons are using flyovers daily and they feel the difference between the previous and the current situation of the time saving.

Figure 02

3. My 3rd observation was made to find out who are the majority using this flyovers. It has been observed that there is more than 60% personnel are the users of public transports. Following details in Figure 03 were taken according to the observations made.

Figure 03

4. My next observation shows in figure 04 and Figure 5, Average serving time per a journey Vs person. According to chart it says that the actual time period is very less comparing before situation. According to research 90% time saved. As a result air pollution, Diesel/petrol consumption, Police man power, Vehicle wastage etc minimize proportionally.

Figure 04

Figure 5

Finally, during the research, my hypothesis was proved, because the majority stated that construction of flyovers where the traffic jammed areas are the best remedy for the issue.



1. In order to minimize the city traffic congestion, the authorities have only handful of options. The highly effective solutions practice in other countries as follows..

a. Controlling traffic using methodical light system,

b. Directing traffic through one direction of the full carriageway.

c. Controlling traffic with the aid of authorized personnel (police men) d. Construction of flyovers.

In Sri Lanka the respective authorities has constructed six flyovers at highly congested areas in Colombo suburbs. These locations were selected according the statistical surveys carried out by the experts in this field. However, it is inevitable that this effort has not succeeded in few locations as anticipated. Hence, during this research, I developed an argument to justify that the construction of flyovers are the best remedy for this issue by obtaining the opinion from the general public as my target group. This is the target group for early surveys carried out by the RDA in conjunction with University of Moratuwa to justify the construction of flyovers in Colombo suburbs as well.

2. A well developed transportation system plays a great role for any country of the world. The country has developed up to a certain extent throughout the time but the transportation has not sufficient to cater for the increasing demand of Road network. The construction of many flyovers in our most needed area, responsibility of the government but also depends on the attitude of the people especially all drivers and pedestrians. The also should give their fullest support to the current rules and regulations.

3. During the research, my hypothesis was proved, because the majority stated that construction of flyovers where the traffic jammed areas are the best remedy for the issue.

4. After carrying out a survey and analyzing the data, the following are the details of identified benefits and summarized as follows.

Avoids traffic congestion - through segregation and priority

Speedy - shortens journey times

Smooth - no violent movements vertically, laterally, or backwards/forwards


Compatible with pedestrians in giving pedestrianised areas

Reduces the capacity for accidents

5. Moreover in this survey and analyzing the data, the few limitation and barriers identified as follows;

Complicated, and costly, due to the need for large physical structures and for maintenance

Their height can be obtrusive.

c. Require a significant engineering and time-consuming to construct.

6. It has come into the notice of the urban planers that in order to improve the transport system a multi modal approach should be made. All in all, the main focus is on the development of more roads and more effective mass transportation. Priority should be given to the commuter and his requirement for a safe problem free movement space.

7. Finally, according to collected primary/secondary data. Following actions can be taken to minimizing traffic jammed. Without any delay some facts are presently available and not to standard.

Banning of All On-Street Parking for Vehicles in City Limits

Traffic Signal Lights

Introduction of Substitute Roads to Main Roads

Widening of roads

Restriction of Slow Moving Traffic and Heavy Vehicles During Rush Hours

Separating Pedestrians from Active Traffic Flow

Proper maintenance of roads- specially culvert and rainy period road situation required quickly repairing system

Creating driving discipline - presently available new driving licence card entering system

Implementation of New Highways Connecting Main Cities of The Country

Electronic Traffic Monitoring Systems for Main Cities - specially actual road jammed persons rules violated persons capturing part

Discouraging Individual Vehicles Entering Cities (Peak hours container, tractor etc)

Bus Stands (Required up lift and move to main road)

Construction Work (Required combined worked force (RDA/UDA/CEB/NWS&DB)

8. During the last decades the country has developed immensely; therefore the alternative methods to control traffic congestion are highly essential because of the increasing of the vehicles. The government also has the responsibility to put a genuine effort for this other than going only for political achievements however much difficult it is, the importance should be identified and thereby should give priority for the development of this area. There are enough methods and intellectual ideas, which can be utilized to achieve this. Constructing flyovers for some intersections where the traffics are occurred during the peak hours is the best solution for this. But unfortunately this is an area considered least during the last decades. However, number of flyovers has been constructed during last few years and commuters are getting benefits instead of wasting time in traffic congestions. Not only does it help to reduce the time wastage but also helps to increase the productivity of private and public sectors and the economy of Sri Lanka.

9. It can be concluded that the flyovers are good solution for traffic congestion for an intersection unless the capacity of the approach links are upgraded by means of traffic management measures. This can be accepted as an effective solution for traffic congestion in suburban areas where all links are of similar importance. However, this is a good strategy for eliminating the delay at railway crossings.

10. The continuation of the current trend of constructing flyovers will sustain future planning and designing of integrated networked traffic management strategies, thereby contributing to the economy by saving billions of Rupees to the country as well.