OPTIMIZATION MODEL FOR THE PROJECT OF THE THIRD

METRODIAMETER IN SOFIA, ACCORDING TO ITS MAXIMUM

SOCIAL-ECONOMIC EFFICIENCY

Authors: Kaloyan Tsvetkov &Viktor Chaushev 1

ABSTRACT In 2009 Sofia Metropolitan became the main means of mass transportation of passengers in the capital. After

building the second metrodiameter over half of the inhabitants of the capital will have access to rapid

transportation. The purpose of this study is to optimize existing project through a complex of geographical and

interdisciplinary methods, including GIS (Geographic Information System), to its maximum social-economic

efficiency.

Keywords: Sofia Metropolitan, metrodiameter, buffering, passenger traffic, social-economic efficiency

Introduction The theme of the Sofia metro has become extremely popular in the recent years. After the

completion of the first metroradius (Obelya - Serdika) and especially after connecting it with the

newly built second metroradius (Mladost 1 - SU) on the first metrodiameter, the residents and the

visitors of the city felt the advantages of the underground rail. Through it the two largest living areas

of Sofia, Lyulin and Mladost, has been linked together and with the center. Thus, the traffic intensity

in Sofia appeared to have decreased, especially on the transport junctions with “Tsarigradsko shosse”

blvd. With the release of the second metro diameter rapid transportation will finally be available to

over half of the inhabitants of the capital. The topic of further steps in the subway extension will

become very obsolete. On the other hand, much criticism will appear on the existing proposal for a

route for the third metrodiameter and the possible development of the fourth circular metrodiameter.

Parallel to this process, the question about the effectiveness of the existing scheme of mass urban

ground transport will rise, following the operation of the new metrodiameters.

The subject of this study, in view of the foregoing, is the spatial analysis, related to the

optimization possibilities of the third metrodiameter, in order to help make informed management

decisions, using GIS. The study object is the territory of Sofia municipality, its population and

transport system, which connects them, particularly, the subway. The goal of the study is to propose a

model that has greater social and economic efficiency to the currently accepted route but not by much

higher costs for construction. To achieve this goal, the following tasks have to be completed:

To examine in detail Sofia’s General Development Plan, in particular, its communication and

transportation system concerning the electrical transport.

To clarify the structural differences between different types of urban rail - speed tram, LRT

and classic metro.

To obtain a detailed database about the population and infrastructure of the capital.

Spatial analysis:

a) To compare the current plan for the third metrodiameter and the authors’ proposed

project, using GIS;

b) To perform buffering in GIS for all metrodiameters and authors’ project, to detect

potential passenger traffic;

c) To draw conclusions, according to the results for potential passenger traffic, as to which

plan has better social-economic efficiency.

To prepare visualization materials:

a) A scheme of routes and stations of the current plan and authors’ proposal;

b) A scheme of current plan’s buffering;

c) A scheme of authors’ proposal buffering;

1Students, Sofia University “St. Kliment Ohridski”, Tsar Osvoboditel blvd, Sofia 1504.

d) A scheme of all metrodiameters (including this proposal) and possible future extensions

of the metro and the urban transport.

Data and methods To perform a GIS analysis very detailed information about the spatial distribution of population

is needed. Due to the fact that there is not any detailed annual statistics, the authors have used the data

for the control regions (total 1503) of the population from the last Census in 2001. We believe that this

is a serious obstacle in order to achieve the goal of this study, because Sofia has positive natural and

mechanical increase (NSI 2009) and experts estimate that the population already exceeds 1.5 million

people. However, there are no new data.

Sofia became a capital on April 4, 1879 with a population of 12 thousand and had not

increased significantly until 1946 (population in 1946 - 367 thousand people). Therefore, in no way

we can compare Sofia’s subway system to others subway systems of the Western European capitals.

Vienna, which is often compared to our capital, had obtained a subway by 1898 when there were 1.77

million people living.

For the reason that this problem is an object of study by other authors from different scientific

fields such as architecture, geodesy, surveying, computing, spatial statistics and more, (Kotsev 2008),

the authors want to prove to the public that, with the help of modern geographical knowledge,

effective solutions in the field of spatial planning and solving problems of modern cities can be

offered. In the course of work, the authors have understood that GIS is an integral part of the modern

geographical science and it is not a concept of the above scientific fields!

Development and territorial extension of the third metrodiameter’s adopted plan The third diameter, according to the current master

plan will connect the southwest with the northeast part of the

city. Some parts of this route have already been built near to

Poduyane train station. Generally, the route passes through

Knyazhevo quarter - Tsar Boris III Blvd – Patriarh Evtimii

Blvd. – Vasil Levski Blvd – Yanko Sakazov Blvd – Madrid

Blvd – Botevgradsko Blvd. (Fig 1). In connection with the

amendment of Sofia’s Master Plan, Sofia Municipality stated

that it will be built 80% ground as "Speed tram or LRT", and

only in downtown center the route will go underground.

According to Thompson (2003), LRT is designed for

“light traffic and fast movement”. It must have the ability to

carry many passengers, but to stop much more quickly if

needed. It has no different type of intersection on different

levels with the other parts of the transport system, compared

to classic subway. It should be built above ground and in

exceptional cases - underground, only where ground

transition is impossible. The main purpose of this type of

metro is the carriage of quantity of passengers, similar to the

classical subway passenger traffic, but with much less initial

investment in the construction of the infrastructure.

The speed tram is a mode similar to the LRT, but

traffic is much less and the intersection with the other parts

of the transport system is not necessarily taking place at

different levels. A typical example is the speed tram in

Budapest – Line № 4, which connects the northern to the

southern part of Buda, going through Pest. The daily

passenger traffic is about 20 thousand people per hour and in "rush hour" trams move in intervals -

from 1 to 3 minutes. The line is served by tram carriages “Siemens” with total length of 52 meters and

total capacity – around 300 passengers.

The classic type of subway, compared to the three types, is the most expensive to implement,

but is extremely efficient for the transport of large numbers of passengers to medium distances. It must

Fig. 1 Proposed metrostation names for

the adopted plan

run underground, but it is allowed to pass only above ground, where it is possible, and do not impede

the average speed. This is done to reduce the high costs of construction of underground infrastructure

(Cervero 1998).

The main reasons to build the third metrodiameter following the adopted plan are entirely

financial - since already about 70% of the route has been built - these are the routes of trams № 5 and

22, respectively- from Knyazhevo to Ruski Pametnik Sq. and from Poduyane train station to "Iztok"

transfer station. The only part left to be built is the underground central part, which, according to the

Master Plan goes near to the Court House and Vasil Levski Sq., but according to the website of the

Sofia Metropolitan (www.metropolitain.bg) - through the NPC and Sofia University.

The disadvantages of the adopted plan are obvious. Densely populated residential complexes,

such as Levski and, especially, Ovcha Kupel, remain outside of the route. It takes at least 30 – 40

minutes to travel downtown from this living complex in regular traffic (Table 1).

Table 1

Travel Duration from Ovcha Kupel quarter to downtown centre

(Source: www.sumc.bg) l.q. Ovcha Kupel – metrostation Serdika

line and stop Workdays Weekends

Bus line № 11 – l.q. Ovcha Kupel 8:02 8:03

Bus line № 11 – Metrost. “K.Velitchkov” 8:26 8:26

Metrostation “K.Velitchkov” 8:30 8:34

Metrostation “Serdika” 8:34 8:37

Duration 32 min. 34 min.

Price (valid 01.04.10) 1,60 BGN. 1,60 BGN.

In addition, l.q. Ovcha Kupel is extremely bad linked by environmentally clean transport. This

is the only residential complex in Sofia, which is not served by any option of the electrical transport!

If the plan is implemented in this version, Sofia will finally be devoid of any lasting solution for

the transportation of Sofia residents from one point to another without losing more than 20 to 30

minutes in traffic. And at this time the travel from Knyazhevo and Levski to the center does not last

more than 31 minutes, at a price of 1 lv. (Table 2), even in rush hour (8:00 to 9:00 pm)!

Table 2

Travel duration from the last stops of tram lines № 5 and 22 to downtown centre

(Source: www.sumc.bg)

As it is apparent, by reason of the tram routes being separated into a specific part of the

boulevard, the travel duration in workdays and weekends is not changed.

After the comparison the data for the density of the population in Sofia and the adopted route in

GIS environment and by applying the operation "buffering" with radius 500 meters around each

metrostation (application № 1), the following data has been obtained:

People living in 500 m radius around each metrostation - 173 000.

Average passengers per station, per day - 7,500 people.

Length of track - 16 km.

Comparison with the other two metrodiameters is shown in Table 3.

From the foregoing it is clear that the existing route of the Third metrodiameter no longer meets

the recent needs of the capital’s population. The great quantity of stops will significantly slow down

the transportation itself, but more alarming is the fact that the potential traffic is bigger than that of the

second metrodiameter which is determined as classic metro! The fact that it passes through arteries,

Line № 5 Line № 22

stop Workdays Weekends stop Workdays Weekends

„Knyazhevo” 7:59 8:00 „Iztok” transfer st. 8:02 8:07

„Court House” 8:30 8:30 „San Stefano” 8:17 8:22

Duration 31 min. 30 min. Duration 15 min. 15 min.

Price (valid 01.04.10) 1 BGN. 1 BGN. Price (valid 01.04.10) 1 BGN. 1 BGN.

which are considered as border for quarters and even for whole districts in places, but not inside the

quarters, is condemning him to be less used, making it an economically unsound initiative! In other

words, its realization will not really improve noticeably the mobility of Sofia citizens, because they

will lose additional time to reach the station itself, and will not meet the goal of the designers of the

subway - to serve about 70 to 80% of passengers carried in the capital for one day (i.e. about 800

thousand - 1 million daily)! Therefore, the authors will put hereinafter their vision for the development

of the metrodiameter.

Table 3

Comparison between all three metrodiameters

Metrodiameter1 First Second Third

Length 29 km 17 km 16 km2

Number of stations 24 17 23

Population13 285 000 155 000 173 000

Population24 338 000 180 000 184 000

Population1/station 12 000 9 000 7 500

Development and territorial extension of the authors’ project for third metrodiameter This proposed route of the third metrodiameter is

based on the study of the number and distribution of the

population as we stand the idea that the primary

function of the metro is social (carrying a maximum

number of passengers). However, the route is designed

so that the greater part of it is situated above the

ground, in order to reduce to maximum the investment

cost.

Following the analysis in GIS environment of the

population density in Sofia, the most densely populated

living areas of the capital in southwest – northeast

direction are living quarter Ovcha Kupel, living areas

on both sides of Bulgaria Blvd, city center, and living

quarters Hadji Dimitar, Suha Reka and Levski. The

proposed route in the Master Plan does not cover l.q.

Ovcha Kupel, partially covers the living areas west of

Bulgaria Blvd (Buxton, Krasno Selo and Hippodruma),

and from the neighborhoods in the northeast part of

Sofia - partially Suha Reka. As a result, for the

remaining living areas an infrastructure for the

additional inlet transport needs to be built. Therefore, the authors offer the following route: from the

southwest to the northeast - Railway station Gorna Banya - President Lincoln Blvd (l.q. Ovcha Kupel)

– Ovcha Kupel Blvd - Todor Kableshkov Blvd – Bulgaria Blvd - NPC - Vasil Levski Blvd - Yanko

Sakazov Blvd - Vladimir Vazov Blvd. The names of the stations can be seen in Fig. 2 and their

location - on the application № 3.

The route should be built underground in center city areas, from metrostation “Center for

Hygiene” to metrostation “Evlogi and Hristo Georgievi” and from metrostation "Bulgaria" to the

intersection of Tsar Boris III Blvd and Ovcha Kupel Blvd. The rest of the route should be built on

ground. Table 4 shows the main characteristics of the track, compared to the other metrodiameters.

1 Due to the large differences between the routes in the Master Plan and those published on the website of the

Metropolitan (www.metropolitain.bg), it is prudent to select the plan from the company’s website since they are

directly responsible for servicing the metro in Sofia. 2 The value differs from that from the website of the Metropolitan, because GIS calculation can not confirm it!

The values for the length of the diameters are based on GIS calculations. 3 Population living within 500 meters of each subway station

4 Population living within 500 meters of the track

Fig. 2 Proposed names for the metrostations

from the authors' project

This proposal takes into account the decision of the municipality committee on transport,

infrastructure and road safety from October 7, 2009, which states that the third metrodiameter will be

deviated to the l.q. Ovcha Kupel, the main reason - more population served. We take into account also

the remarks of Mr. Stoyan Bratoev – the director of "Metropolitan Ltd., who foresees further deviation

of the second metrodiameter on Bulgaria Blvd.

Table 4

Comparison between all three metrodiameters and authors’ project

The advantages of the proposed project are as follows:

Serves 29% more population, compare to the adopted plan;

After its possible realization, over 69% of the population will have an access to the subway;

Satisfies the need for additional branch of the second metrodiameter onto Bulgaria Blvd and

heads up to the opportunity to consider its eventual split from metrostation "Central Railway Station"

in direction l.q. Slatina and l.q. Druzhba. (See application № 4);

Provides the ability to serve passengers, who are coming every day from Pernik to work in

Sofia, whose amount is more than 14 000 people (Kotsev 2008), without building a new railway

station (railway station “Vardar” on line “Sofia – Pernik”);

The route is served by 14 stations - 9 less than the adopted plan;

There is suitable municipal land to build a train depot to serve the metrodiameter - located

between l.q. Levski-G and l.q. Vrazhdebna, currently occupied by lawns and illegal dumps, as

opposed to the adopted plan, which does not have any suggested land for this purpose.

The project provides a convenient connection with the other two metrodiameters

(metrostations "NPC" and "St. Kliment. Ohridski");

Dismisses the need to deviate the third metrodiameter outside city center;

The realization of this project will also support the realization of the expansions of Todor

Kableshkov Blvd in l.q. Borovo and Ovcha Kupel Blvd in l.q. Slavia, according to the Master Plan and

will serve to avoid the closure of all the busy intersections of Tsar Boris III Blvd., except for that with

Ovcha Kupel Blvd;

Does not fully duplicate any existing tram route (tram № 5 and 22).

However, there are some disadvantages of the proposed project as follows:

The route is longer, compare to the adopted plan. According to GIS calculation – about 1

kilometer more;

GIS analysis shows that the underground part of this project is 0.9 km longer than the

adopted plan (6 km against 5.1 km).

Of course, there are some improvements to be made in the ground public transport. Some parts

of its lines can be used by presenting a valid ticket from the subway (i.e. parts of the lines can be used

as an inlet transport). Through that, there will be a cheap way for more people to use the subway

system, after its completion.

In order to avoid compulsory travel through the center using the subway in order to reach two

outside quarters, the authors are proposing a circular tram route to be built as follows: Adam

Mickiewicz Str. – Beli Dunav Str. – Nicola Zhekov Str. – First Bulgarian Army Blvd. – Rezbarska

1 please, refer to the previous page

2 there again

3 there again

4 there again

Metrodiameter1 First Second Third (authors’

project)

Third

Length 29 km 17 km 17,5 km 16 km2

Number of stations 24 17 14 23

Population13 285 000 155 000 199 000 173 000

Population24 338 000 180 000 238 000 184 000

Population1/station 12 000 9 000 14 000 7 500

Str.– Vladimir Vazov Blvd. – Vitinya Str. – Georgi Spassov Str. – Bojan Magesnik Str. – Assen

Yordanov Blvd – G.M. Dimitrov Blvd. – Philip Koutev Str. – Todor Kableshkov Blvd. – Ovcha

Kupel Blvd. – Montevideo Str. – Peter Dertliev Blvd – Adam Mickiewicz Str. It must run on a part

separated from the roadway, like the one on Bulgaria Blvd. This will be a link between all

metrodiameters through metrostations “Beli Dunav”, “Svoboda”, “Vitinya”, “G.M. Dimitrov”,

“Srebarna”, “Bulgaria”, “Borovo”, “Ovcha Kupel 2” and “Zapaden Park”. The route serves as the

fourth circular diameter and establishes direct correspondence via metro to almost anywhere in Sofia!

Conclusion The newly built Sofia metropolitan is the most modern installation – a future benefit of all

citizens and guests of the capital. As, after its completion, it must perform the main function of urban

mass transport, it should be built with the use of the most effective social, structural and financial

manner. With the realization of this optimization model for the third metrodiameter, the social aspect

will be observed but, unfortunately, at the expense of the financial one. However, the financial burden

would be less than if, after the realization of the third metrodiameter, according to the adopted plan, an

additional infrastructure for inlet transport in densely populated neighborhoods was built.

Due to the complexity of the studied problem, the authors do not claim to be exhaustive and will

gladly accept any scientifically based criticism on these issues. The model with a circular buffering

radius, which does not take into account buildings and other obstacles to the access to the subway, is

not the most effective way to calculate the transport accessibility. In the future, an analysis in

multimodal regime of buffering which takes into account these obstacles should be considered.

The authors wish to thank the Asst. Prof. PhD Alexander Kotsev, for the cooperation in the

work with GIS and gathering statistical information and the Assoc. Prof. PhD Veselin Boyadjiev.

Applications

Application 1. Buffering of the metrostations of the adopted plan for the third metrodiameter

Application 2. Buffering of the metrostations of the authors’ project for the third metrodiameter

Application 3 Scheme of the routes and stations of the adopted plan and authors’ project

Application 4. Proposal for future deviations of the second metrodiameter and for circular tram line

References 1. Коцев, А., Моделиране и картографиране на достъпността на населението в София до

обществени услуги с помощта на ГИС, София 2008. (автореферат)

2. Cervero, R., The Transit Metropolis - A Global Inquiry, Island Press 1998, ISBN 1-55963-

593-6.

3. Thompson, Gregory L., Defining an Alternative Future: Birth of the Light Rail Movement in

North America, US Transportation Research Board 2003.

4. http://www.bg.wikipedia.org/wiki/%D0%A1%D0%BE%D1%84%D0%

B8%D0%B9%D1%81%D0%BA%D0%BE_%D0%BC%D0%B5%D1%82%D1%80%D0%BE

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6. http://www.forum.gtsofia.info/index.php?topic=1038.0

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11. http://www.sofproect.com/