For a solution to Dhaka's traffic congestion
Shafiq Alam | Monday, 2 June 2008
WHEN the population of a mega city exceeds its acceptable limit, the traffic congestion is an obvious result. It happened in many cities. Dhaka is no exception. We would see this in many other cities as well.
In 1856, England had initiated the process and in 1863 a four-km strip of underground metro railway was operational in London. Even now metro is considered as the most effective mode of transport all over the world.
A solution to solve the problem of congestion by surface transport system depends entirely on the population and its growth. The population of Dhaka city is over 15 million and this would double by 2015. Transportation engineers, after studies, have classified mass transit system into two categories, the heavy metro or underground metro rail, and the light metro or the sky train and mono rail. As the population of Dhaka is very high and growth rate is high as well, light metro won't suit.
In the later part of the last century light metro was introduced to few places as a test case. Its passenger catering capacity is much less than that of underground metro rail and people always feel psychological stress to go upward. In case of an accident sky train or monorail will directly fall on roads killing a large number of passengers. Besides, it is absolutely impossible for light metro to go vertically upward or downward for expansion of its network. In hot and humid Dhaka, the temperature would be very high at the sky train or monorail station entrance. But the passengers would get conditioned air inside the coach. This temperature difference would severely affect the passengers. Moreover, the look of Dhaka would be affected and the stations would be dirty. As light metro can carry fewer passengers, people have to depend on the other transport system. And this would be sensible.
Dhaka has much less limitation of roads. There is no possibility to build more roads so that the city had the required road networks. That's a good reason for not increasing the number of surface transports. Roads are already crammed with vehicles. More buses would only aggravate the situation. On the other hand, the present transport system is causing heavy pollution. City transport planners need to free people from congestion as well as pollution.
The following factors need to be considered; comparative study, construction process, cost, return and subsidy factor, affordability, sustainability, future expansion, comfort, security, coverage, economic gain, and environmental impact.
Comparative studies show that underground mass transit system (MRT) would more convenient as it can carry at least five to 10 times more passengers than other system including LRT and BRT.
The required subway tunnel for MRT can be constructed in two ways: a) cut, and cover method b) TBM (tunnel boring machine) method.
The cut and cover is a simple process. A couple of routes can be constructed simultaneously, using it without hampering traffic movement. The cost would be Tk 1.20 billion-Tk 1.50 billion (120-150 crore) per km. China constructed about 27 km of subway, using it, in one and a half years. For Dhaka it would take three and a half to four years for complete setup at a shallow depth like the Osaka subway of Japan.
The total cost would be about taka 70 billion (7000 crore) using the cut and cover method. The system would need no subsidy from the government, as the IRR (internal rate of return) is positive here for the underground system. The IRR is negative for mono/sky.
Affordability is related to fare, and the fare for the underground system would be just like bus.
An engineer, the writer can be reached at e-mail: [email protected])
In 1856, England had initiated the process and in 1863 a four-km strip of underground metro railway was operational in London. Even now metro is considered as the most effective mode of transport all over the world.
A solution to solve the problem of congestion by surface transport system depends entirely on the population and its growth. The population of Dhaka city is over 15 million and this would double by 2015. Transportation engineers, after studies, have classified mass transit system into two categories, the heavy metro or underground metro rail, and the light metro or the sky train and mono rail. As the population of Dhaka is very high and growth rate is high as well, light metro won't suit.
In the later part of the last century light metro was introduced to few places as a test case. Its passenger catering capacity is much less than that of underground metro rail and people always feel psychological stress to go upward. In case of an accident sky train or monorail will directly fall on roads killing a large number of passengers. Besides, it is absolutely impossible for light metro to go vertically upward or downward for expansion of its network. In hot and humid Dhaka, the temperature would be very high at the sky train or monorail station entrance. But the passengers would get conditioned air inside the coach. This temperature difference would severely affect the passengers. Moreover, the look of Dhaka would be affected and the stations would be dirty. As light metro can carry fewer passengers, people have to depend on the other transport system. And this would be sensible.
Dhaka has much less limitation of roads. There is no possibility to build more roads so that the city had the required road networks. That's a good reason for not increasing the number of surface transports. Roads are already crammed with vehicles. More buses would only aggravate the situation. On the other hand, the present transport system is causing heavy pollution. City transport planners need to free people from congestion as well as pollution.
The following factors need to be considered; comparative study, construction process, cost, return and subsidy factor, affordability, sustainability, future expansion, comfort, security, coverage, economic gain, and environmental impact.
Comparative studies show that underground mass transit system (MRT) would more convenient as it can carry at least five to 10 times more passengers than other system including LRT and BRT.
The required subway tunnel for MRT can be constructed in two ways: a) cut, and cover method b) TBM (tunnel boring machine) method.
The cut and cover is a simple process. A couple of routes can be constructed simultaneously, using it without hampering traffic movement. The cost would be Tk 1.20 billion-Tk 1.50 billion (120-150 crore) per km. China constructed about 27 km of subway, using it, in one and a half years. For Dhaka it would take three and a half to four years for complete setup at a shallow depth like the Osaka subway of Japan.
The total cost would be about taka 70 billion (7000 crore) using the cut and cover method. The system would need no subsidy from the government, as the IRR (internal rate of return) is positive here for the underground system. The IRR is negative for mono/sky.
Affordability is related to fare, and the fare for the underground system would be just like bus.
An engineer, the writer can be reached at e-mail: [email protected])