Article
citation information:
Świderski,
A., Sobczuk, S., Borucka, A. Analysis of changes in
transport processes in Warsaw public transport in the face of disruptions in
2019-2022. Scientific Journal of Silesian University of
Technology. Series Transport. 2024, 124,
229-241. ISSN: 0209-3324. DOI: https://doi.org/10.20858/sjsutst.2024.124.16.
Andrzej
ŚWIDERSKI[1], Sebastian SOBCZUK[2], Anna BORUCKA[3]
ANALYSIS
OF CHANGES IN TRANSPORT PROCESSES IN WARSAW PUBLIC TRANSPORT IN THE FACE OF
DISRUPTIONS IN 2019-2022
Summary. Public transport
focuses on meeting the transport needs of people both within the city and in
the suburban area. Passenger transport is a key element of sustainable development
and improving the quality of life in agglomerations because it provides
mobility for residents and tourists. In recent years, residents have become
increasingly willing to use public transport. However, this trend was disrupted
as a result of global changes taking place in the years 2019 - 2022.
The aim of this publication was to analyse and assess the impact of crisis
situations on the implementation of transport processes using the example of
public transport in Warsaw. It has been shown that events such as the COVID-19 pandemic or the war in Ukraine also had a
significant impact on the functioning of transport processes in Warsaw public
transport. The study made it possible to identify recommendations aimed at
securing the operation of public transport in the event of similar threats in
the future.
Keywords: public transport, passenger transport,
transport processes, urban transport system, transport needs, COVID-19 pandemic impact
1. INTRODUCTION
Public urban
transport ensures the mobility of people, bringing many benefits, both at the
level of the individual and the entire society [1]. It is a key element of
sustainable development and improvement of the quality of life in large urban
agglomerations [2]. Events in recent years show that, apart from the
development of urban transport, the resilience and stability of transport
processes when exposed to disruptions, especially global ones, play an
important role in assessing its quality [3, 4]. In December 2019, the first
infection with the SARS-CoV-2 virus was reported in
China, and it soon spread around the world, causing the COVID-19
pandemic [5]. This event dramatically changed the perception of public
transport, which was then identified as the main vector of the spread of
infection in densely populated areas, which in turn led to a decline in the
interest in public transport [6]. Another event with serious consequences was
Russia's invasion of Ukrainian territories in February 2022, which started the
war.
The consequence of this was the migration of the Ukrainian population to other
countries in search of their safety, protection, and help [7]. This event had
an impact on public transport in many Polish cities, including Warsaw. Taking
into account the indicated events and the fluctuations related to them, the
scientific goal of the research was to analyse and evaluate the impact of
crisis situations on the implementation of transport processes using the
example of public transport in Warsaw. For this purpose, the following
hypothesis was formulated: "global threats from 2019 to 2022 had a
significant impact on the implementation of transport processes in Warsaw
public transport, causing changes in transport needs". As a result, areas
requiring improvement were defined and recommendations were made to protect
public transport in the event of similar threats in the future.
2. LITERATURE REVIEW
The impact of global threats on the
functioning of public transport is widely discussed in the literature [8]. In
the context of epidemic disruptions, there is a need to adjust restrictions to
the actual level of risk, emphasizing that the implemented solutions will not
always meet the expectations of users and the prevailing situation [9].
Research related to the impact of restrictions on the functioning of society
showed a much lower level of mobility during the period of increased
restrictions [10]. Other studies show that passengers were relatively relaxed
about vehicle occupancy restrictions and often did not respect social
distancing [11]. It has also been shown that there is a negative relationship
between passenger traffic in public transport and the number of new COVID-19 cases [12]. Moreover, it was shown that as the
number of new infections decreased, the use of public transport began to increase,
which indicates that the demand for transport largely depends on the sense of
security of passengers and the reliability and readiness of the transport means
themselves [13, 14]. An analysis of changes in the daily mobility of Warsaw
residents showed that passenger traffic weakened as the pandemic escalated and
subsequent restrictions were introduced [15]. The outbreak of the pandemic also
resulted in a change in preferences and travel patterns [16]. Moreover, it was
shown that the lower use of public transport during the pandemic was related to
changes in the structure of tickets purchased [17]. The publications also
detail solutions and directions of the development of Warsaw public transport,
emphasizing that global threats can be used as an opportunity to remodel
selected areas of public transport in accordance, among the others with the
concept of "smart mobility" [18, 19]. The literature review allowed
us to assume that there is a research gap in the area of analysis and
assessment of processes taking place in urban public transport in Warsaw in the
light of global disruptions in 2019 - 2022.
3. MATERIALS AND METHODS
The
publication presents the results of the analysis and evaluation of the impact
of global threats on the implementation of transport processes described using
quantitative indicators, such as transport performance and the number of
passengers transported, as well as changes in transport needs in terms of the
number and structure of tickets sold. The case study for the research was the
city of Warsaw (the capital of Poland) together with the neighbouring towns
that together form the Warsaw agglomeration. The source materials for the
research were obtained from the statistics of the Warsaw City Hall Office and
the Public Transport Authority in Warsaw (ZTM) [20,
21]. The data collected was divided into periods:
pre-pandemic, pandemic and since the outbreak of the war in Ukraine, which were
subjected to exponential smoothing using the Brown or Holt method, depending on
the characteristics of
a given time series [22, 23]. According to Brown's method, the following
equation was used for the first time moment t=1:
(1)
For the
subsequent time moments, the following relationship was used:
(2)
where: 
- forecast value for the moment t;
- actual value for the moment t-1;
– exponential
smoothing level coefficient, 
In
turn, smoothing models using the Holt method were built in such a way that for
the time moment t>n:
(3)
where: - forecast value for the moment t;
– smoothed value of the forecast variable at the moment n; 
– assessment of trend growth at the moment n; n
- number of elements in the time series.
Taking into account that:
(4)
(5)
(6)
(7)
where: 
– smoothed value of the forecast variable at the
moment t-1; 
– smoothed
value of the trend increase at the moment t-1; 
– exponential smoothing level coefficient, 
– trend smoothing level coefficient, 
In
both methods, the parameters α, β were selected as to achieve
a high fitting of the model with a real data by minimizing the mean absolute
percentage error (MAPE) and the root mean squared
error (RMSE) [24]:
(8)
(9)
Then, linear regression was determined for the exponential smoothed
models:
(10)
where: 
– value of the dependent variable at the
moment t; 
– value of the independent variable
(predictor) at the moment t; a – regression coefficient (slope); b –
intercept.
Fitting of the regression model was
evaluated using the R2 determination
coefficient:
(11)
Consequently, by determining the
parameters of the linear mathematical model, the changes taking place in the
implementation of transport processes were analysed and evaluated.
4. THEORETICAL BACKGROUND
Public transport in the Warsaw
agglomeration is a transport system composed of bus and rail means of
transport, which vary in terms of the number of passengers served and the
transport performance (Table 1) [21].
Tab. 1
Number of passengers transported and
transport performance by individual means of transport in Warsaw public
transport in 2022
|
Means of transport |
Number of passengers |
Transport performance |
||
|
[mil] |
[%] |
[mil VKT] |
[%] |
|
|
Buses (MZA and other
operators) |
403,03 |
46,7 |
119,81 |
44,71 |
|
Warsaw Trams (TW) |
247,22 |
28,6 |
51,26 |
19,1 |
|
The Warsaw Metro (MW) |
160,82 |
18,6 |
44,47 |
16,6 |
|
Masovian Railways (KM) |
30,96 |
3,6 |
34,18 |
12,8 |
|
Fast City
Railway (SKM) |
17,76 |
2,0 |
16,03 |
6,0 |
|
Warsaw Commuter Railway (WKD) |
3,66 |
0,4 |
2,24 |
0,8 |
The metropolitan authorities are
taking steps to develop sustainable transport, including the integration of
public transport services in terms of tariffs, tickets, transfers, and
timetables. Much attention is paid to reducing exhaust emissions and noise
levels, regularly replacing old vehicles with new ones. Actions are also taken
to reduce traffic congestion by providing more convenient conditions for
travelling by public transport [20]. The outbreak of the COVID-19
pandemic led to a different functioning of public transport due to the
imposition of limits on the number of passengers transported in the individual
means of transport. The restrictions introduced significantly limited transport
possibilities, leading to a discrepancy between demand and supply for
transport. On the other hand, society's fears of contracting the virus reduced
the number of travellers, which caused some vehicles to operate with minimal
occupancy [12, 16]. Another global threat affecting Warsaw public transport was
the Russian invasion of Ukraine on February 26, 2022. The huge influx of
immigrants translated into greater passenger traffic in many Polish cities,
which in support, provided among the others, free travel on public transport
[7]. Taking into account the population growth in Warsaw caused by the influx
of refugees and, therefore, the increased demand for passenger transport, it is
noted that this may be an opportunity to reduce losses caused by the COVID-19 pandemic.
5. RESULTS AND DISUSSION
5.1. Tickets sold
Demand for transport services can be
expressed by the number of tickets sold for public transport in a given area.
It is an indicator used to analyse the popularity and
availability of public transport, and changes in travellers’
preferences, as well as to assess the functioning of the urban transport
system. Data on the number of tickets sold is crucial for transport organizers
and operators because based on sales results, decisions are made regarding
applicable ticket offers, routes served, and even planning the development of
the transport network.
Analysing data on the structure of ticket
sales in the years 2018 - 2022, it can be concluded that the greatest
popularity concerned 20-minute time tickets, because on average 3.6 million of
them were sold per month. In second place were time
tickets (75 or 90 minutes) with average sales of PLN 2.69 million per month.
Significantly fewer people bought long-term tickets, on average 352.9 thousand
a month. Passengers were the least likely to decide to purchase short-term
tickets because the average sale was 161.9 thousand a month. Changes in the
structure of tickets sold were seasonal, depending on a specific month of the
year. The highest results were usually recorded in October, due to the return
to educational institutions and workplaces after the holiday period. The lowest
sales occurred in the winter months, which may have resulted from the more
frequent use of own means of transport due to weather conditions, as well as
from reduced mobility due to the Christmas break or holidays. There were also
differences in the structure of tickets sold over the years. An example of this
is in 2020, when the outbreak of the COVID-19
pandemic led, among the others, to the reduction of the activity and mobility
of society due to the applicable restrictions and the so-called lockdown. The
consequence of this were changes in transport needs, which are reflected in the
structure of tickets sold in
March-June 2020, as the share of short- and long-term tickets decreased. The
increase in ticket sales has been noticeable only since March 2022, which is
not only related to the end of the epidemic crisis but is also the result of
demographic changes in the Warsaw agglomeration due to the influx of Ukrainian
immigrants (Fig. 1) [7].
Fig. 1. Quantitative structure of
tickets sold on Warsaw public transport
Then, a study was conducted on the
changes in the total number of tickets sold. These sales amounted to: in 2018 -
6.98 million, in 2019 - 7.08 million, in 2020 - 4.88 million, in 2021 - 6.64
million, in 2022 - 8.47 million. Such high results translate into average
annual sales of 6.81 million tickets. It is worth paying attention to the
results from 2020 and 2022. They show the highest deviations from the
arithmetic mean, which indicates the disruptions occurring at that time. The
study showed that before the outbreak of the COVID-19
pandemic, there was an increasing trend in ticket sales by 29.86 thousand per
month (Fig. 2a). Since the outbreak of the epidemic
threat, the rate of change has increased significantly - to 196.49 thousand
(Fig. 2b). In turn, in the period since the outbreak
of the conflict in Ukraine, the largest increase in sales occurred - by 315.72
thousand per month (Fig. 2c). Therefore, in the years
2018 - 2022, the total number of tickets sold in Warsaw public transport showed
an upward trend, with the pace of change varying depending on the specific
period. Moreover, paying attention to the actual values in individual months
and the characteristics of the models built, it can be concluded that the
overall ticket sales depended on the crisis events considered. In terms of the COVID-19 pandemic, this is confirmed by the first months
after the virus appeared in Poland, i.e. March and April 2020 (Fig. 2b). The impact of the war and the related influx of
immigrants is shown in the period from February to July 2022 (Fig. 2c).
Table 2 presents the parameters of
the exponential smoothing models of the total number of tickets sold, along
with prediction errors. Parameters and determination coefficients for the
established linear trends in individual periods are also presented.
Tab. 2
Parameters of smoothed models and
linear trends for the total number of tickets sold
|
Period: |
Pre-pandemic (a) |
Pandemic (b) |
Since the UA-RUS war (c) |
|
Exponential smoothing models |
|||
|
α |
0,1871 |
0,7484 |
0,8180 |
|
RMSE |
578559,29 |
1141982,20 |
713804,97 |
|
MAPE |
6,84% |
22,08% |
5,93% |
|
Linear models (trends) |
|||
|
form |
y = 29858x + 6×106 |
y=196492x + 3×106 |
y = 315724x + 7×106 |
|
a |
29858 |
196492 |
315724 |
|
R2 |
0,63 |
0,75 |
0,80 |
Fig. 2. Total number of tickets sold
in the pre-pandemic period (a),
pandemic period (b) and since the outbreak of the war in Ukraine (c)
The number of tickets sold on Warsaw
public transport provides important information about the functioning of the
transport system in terms of demand and availability of public transport among
residents. However, it should be borne in mind that the sales indicator is
subject to an error resulting from situations in which some passengers use
public transport without having
a ticket. Such phenomena not only have a negative impact on the financial
condition of carriers, but also disrupt the reliability of data on ticket
sales, and thus the flow of passengers and demand for transport. Although many
residents still travel without a travel document, ZTM
data from 2019 to 2022 optimistically show that Warsaw public transport is
characterized by a low share of people travelling without a ticket, with an
average of only 2.61% of all monthly passengers [21].
5.2. Transport performance
In passenger transport, one of the
basic indicators is transport performance, which in the urban public transport
system is expressed in vehicle-kilometres [VKT] and determines the length of the distance travelled by
the vehicle in a specific time [21]. Warsaw public transport generated
respectively: in 2019 - 231.623 million VKT, in 2020
- 195.398 million VKT,
in 2021 - 188.087 million VKT, and in 2022 - 194.192
million VKT. This means that until the outbreak
of the COVID-19 pandemic (2019), transport means
performed more transport than during the pandemic (2020 - 2022), and the result
from 2022 is noteworthy, indicating
a gradual return to pre-pandemic level. The study showed that before the
outbreak of the COVID-19 pandemic, an increasing
trend was observed by 113.85 thousand VKT per month
(Fig. 3a). Since the spread of SARS-CoV-2 in Poland, there has been a change in the direction
of development of the examined feature - a decrease of 15.14 thousand VKT per month
(Fig. 3b). Since the outbreak of the war in Ukraine,
an increasing trend in transport performance has been observed again by 100.1
thousand VKT per month (Fig. 3c).
This shows that in the years 2019 - 2022, the examined feature showed variable
directions of development, depending on the disturbances occurring at that
time. It can therefore be concluded that the outbreak of the COVID-19 pandemic in Poland led to a significant decline in
transport performance in Warsaw public transport. Moreover, the trend
determined for the period since the escalation of the war in Ukraine shows that
the level of implementation of transport processes in terms of vehicle-kilometres generated is gradually returning to the
pre-pandemic state. This phenomenon is related not only to the development of
the transport network, increasing the fleet of vehicles and changes in their
frequency [20,21], but also depends on the demand for
passenger transport, which, since the outbreak of the war, has been shaped not
only by the needs of the inhabitants of the agglomeration but also by those
immigrants settling in this area [7].
Fig. 3. Total transport performance
generated by Warsaw public transport in the pre-pandemic period (a), pandemic
period (b) and since the outbreak of the war in Ukraine (c)
Table 3 presents the parameters of
the exponential smoothing models of transport performance along with prediction
errors, which prove that the models fit the real data well. Parameters and
determination coefficients for the established linear trends in particular
periods are also presented.
Tab. 3
Parameters of smoothed models and
linear trends for total transport performance
|
Period: |
Pre-pandemic (a) |
Pandemic (b) |
Since the UA-RUS war (c) |
|
Exponential smoothing models Exp. model Exp. model Exp. model |
|||
|
α |
0,4077 |
0,0672 |
0,2722 |
|
β |
0,2987 |
- |
- |
|
RMSE |
1159022,78 |
735102,68 |
989543,24 |
|
MAPE |
5,90% |
3,71% |
4,79% |
|
Linear models (trends) |
|||
|
form |
y = 113854x + 1×107 |
y = -15142x + 2×107 |
y = 100105x + 2×107 |
|
a |
113854 |
-15142 |
100105 |
|
R2 |
0,69 |
0,73 |
0,61 |
5.3. Passengers carried
The number of passengers using
public transport reflects the demand for transport services provided by public
transport operators. This is a key indicator describing the implementation of
transport processes, based on which it is possible to determine how the
transport needs of residents of the Warsaw agglomeration have changed under the
influence of crisis events. ZTM in Warsaw keeps only
annual statistics on the number of passengers transported by public transport.
From 2014 to the end of 2021, the values were estimated manually. From 2022,
in order to increase the accuracy and reliability of statistics, the passenger
counting method has changed as it is based on several data sources [21].
Therefore, apart from the crisis events considered, the number of people
transported by Warsaw public transport will also depend on the passenger
counting method.
Statistics from 2014 to 2023 were
taken into account, showing that an average of 1,019.2 million people used
Warsaw public transport annually [21]. Data from 2020 (726.1 million), 2021
(809.4 million) and 2022 (863.5 million) show the highest deviations from the
arithmetic mean, which indicates the disruptions taking place then. The study
showed that before the outbreak of the COVID-19
pandemic, the number of passengers increased by 15.86 million annually, which
indicates the increasing importance of urban public transport. As a result of
the outbreak of the pandemic and its consequences, the number of people
transported in the Warsaw agglomeration decreased from 1,201.5 million in 2019
to 726.1 million in 2020, i.e. by as much as -39.56%. As a result, since 2020,
there has been a decreasing trend in the number of people transported per year,
at the level of -102.96 million, which only proves how serious the effects of
the pandemic were on public transport. In 2022, the number of passengers
transported increased by 54 million (+6.67%) compared to 2021, and in 2023 by
92.32 million (+10.7%) compared to 2022. As a result, in the period since the
escalation of the Russian-Ukrainian conflict, we have been observing an
increasing trend in the number of travellers, which
shows that the influx of refugees to Warsaw also translated into an increase in
passengers of the public transport. Considering the characteristic of the
smoothed model and the growing trend for the period since the outbreak of the
Russian-Ukrainian conflict, it can be assumed that in the future the number of
people using Warsaw public transport will continue to increase, which is
a desirable phenomenon from the perspective of sustainable development of the
city (Fig. 4).
Fig. 4. Total number of passengers
transported in the years 2014 - 2023
Table 4 contains parameters of the
exponential smoothing model for the total number of passengers transported,
along with prediction errors, which prove that the model fits the real data
well. In addition, parameters and determination coefficients for the
established linear trends in individual periods are presented.
Tab. 4
Parameters of the smoothed model and
linear trends for the number of passengers transported
|
Exponential smoothing model |
|||
|
α |
0,8231 |
||
|
RMSE |
162,7356 |
||
|
MAPE |
10,15 % |
||
|
Linear models (trends) |
|||
|
Period: |
Pre-pandemic |
Pandemic |
Since the UA-RUS war |
|
form |
y=15,862x+1073,6 |
y=-102,96x + 1792,6 |
y = 44,457x + 409,31 |
|
a |
15,862 |
-102,96 |
44,457 |
|
R2 |
0,92 |
0,52 |
0,99 |
6. CONCLUSIONS AND RECOMMENDATIONS
Global
threats from 2019 to 2022, such as the COVID-19
pandemic and the conflict in Ukraine, had an impact on the functioning of the
urban public transport system in Warsaw. The significance of the impact of
these events is confirmed by fluctuations in the indicators describing the
implementation of transport processes, such as transport performance and the
number of passengers transported. As a result of the disruptions, the transport
needs of residents of the Warsaw agglomeration also changed significantly, as
evidenced by the analysis of the structure and ticket sales. During the COVID-19 pandemic, a serious decline in the number of travellers and demand for passenger transport was observed,
therefore it is reasonable to implement solutions that will increase the
stability of transport processes in the event of similar threats in the future.
It is
recommended to:
-
develop an action strategy for the
operation of transport in a state of renewed threat, taking into account the
levels (transition phases) of the epidemic and the corresponding specific
restrictions;
-
increase the sense of safety among
passengers and employees, thanks to the implementation of system solutions with
a clearly defined division of tasks between the authorities, the organizer and
transport operators;
-
develop and enforce safety standards and
crisis response procedures with close cooperation between all entities of the
public transport system;
-
introduce additional solutions to reduce
the risk of infection and maintain high quality of services provided (during
the threat and restrictions in force);
-
provide broader support to transport
organizers in the implementation of preventive and control activities by
sanitary services, law enforcement services and local government authorities
(in the event of renewed threats and mobility restrictions);
-
promote appropriate behaviour when using
public transport, including appropriate passenger behaviour during the
pandemic.
Referring to the conflict in
Ukraine, the study shows that this event was not as important and direct in its
consequences for Warsaw public transport as the COVID-19
pandemic.
Moreover, from the perspective of process implementation and demand shaping, it
brought benefits because the influx of refugees to Warsaw translated into
greater demand for passenger transport and, as a result, also into higher
ticket sales.
References
1.
Murawski
Jakub, Emilian Szczepański, Ilona Jacyna-Gołda, Mariusz Izdebski, Dagmara Jankowska-Karpa.
2022. „Intelligent
mobility: A model for assessing the safety of children traveling to school on a
school bus with the use of intelligent bus stops”. Eksploatacja i
Niezawodność - Maintenance and Reliability 24(4): 695-706. DOI: https://doi.org/10.17531/ein.2022.4.10.
2.
Jacyna
Marianna, Mariusz Wasiak.
2017. “The study of transport impact on the environment with regard to
sustainable development”. Vibroengineering
Procedia 13: 285-289. DOI: https://doi.org/10.21595/vp.2017.19093.
3.
Kukulski Jacek, Konrad Lewczuk, Ignacy Góra, Mariusz
Wasiak. 2023.
„Methodological aspects of risk mapping in multimode transport systems”. Eksploatacja
i Niezawodność - Maintenance and Reliability 25(1): 19. DOI: https://doi.org/10.17531/ein.2023.1.19.
4.
Kaczorek Maciej, Marianna Jacyna. 2022.
“Fuzzy logic as a decision-making support tool in planning transport
development”. Archives of Transport
61(1): 51-70. DOI:
https://doi.org/10.5604/01.3001.0015.8154.
5.
Bucsuházy Kateřina, Robert Zůvala, Jiří Ambros. 2023. “Analysis of Covid restrictions’ influence on road traffic crashes and
related road users’ behaviour in the Czech Republic”.
Archives of Transport 66(2): 109-121.
DOI: https://doi.org/10.5604/01.3001.0053.6084.
6.
Jaroń Agata, Anna Borucka, Rafał Parczewski. 2022. „Analysis of the
Impact of the COVID-19 Pandemic on the Value of CO2 Emissions from Electricity
Generation”. Energies 15(13). DOI:
https://doi.org/10.3390/en15134514.
7.
Kasińska-Metryka Agnieszka, Karolina Pałka-Suchojad. 2023. The Russia-Ukraine War of 2022:
Faces of Modern Conflict. London: Routlege. ISBN: 9781003341994.
8.
Niewczas Andrzej, Łukasz Mórawski,
Joanna Rymarz, Ewa Dębicka, Piotr Hołyszko. 2023. „Operational
risk assessment model for city buses”. Eksploatacja i
Niezawodność - Maintenance and Reliability 25(1): 14. DOI: https://doi.org/10.17531/ein.2023.1.14.
9.
Betkier Igor. 2020. “Safety of Urban
Transport Users in The Time of Covid-19”. European Research Studies Journal 23: 99-115. DOI: https://doi.org/10.35808/ersj/1856.
10. Stępień
Joanna, Tomasz Michalski, Jakub Grabowski, Przemysław Waszak, Maja Grabkowska,
Aleksandra Macul, Jakub Rojek. 2021. „Social response
and spatial mobility change due to Covid-19 pandemic in Poland”. Geographica
Polonica 94: 381-396. DOI: https://doi.org/10.7163/GPol.0210.
11. Bauer
Marek, Wiesław Dźwigoń,
Matthias Richter. 2021. „Personal safety of passengers
during the first phase Covid-19 pandemic in the opinion of public transport
drivers in Krakow”. Archives of Transport 59: 41-55. DOI:
https://doi.org/10.5604/01.3001.0015.0090.
12. Borkowski
Przemysław, Magdalena Jażdżewska-Gutta, Agnieszka Szmelter-Jarosz.
2021. „Lockdowned: Everyday mobility changes in response to
COVID-19”. Journal of Transport Geography 90: 102906. DOI:
https://doi.org/10.1016/j.jtrangeo.2020.102906.
13. Monterde-i-Bort Hector,
Matus Sucha, Ralf Risser, Tatiana Kochetova. 2022. „Mobility Patterns and Mode
Choice Preferences during the COVID-19 Situation”. Sustainability 14(2): 768. DOI: https://doi.org/10.3390/su14020768.
14.
Kozłowski Edward, Anna Borucka, Piotr
Oleszczuk, Norbert Leszczyński. 2024. „Evaluation of
readiness of the technical system using the semi-Markov model with selected
sojourn time distributions”. Eksploatacja i
Niezawodność - Maintenance and Reliability 26(4). DOI: https://doi.org/10.17531/ein/191545.
15.
Macioszek Elżbieta, Agata Kurek. 2021.
„Extracting Road Traffic Volume in the City before and during covid-19 through
Video”. Remote Sensing 13: 2329. DOI: https://doi.org/10.3390/rs13122329.
16. Kłos-Adamkiewicz
Zuzanna, Piotr Gutowski. 2022. „The Outbreak of COVID-19
Pandemic in Relation to Sense of Safety and Mobility Changes in Public
Transport Using the Example of Warsaw”. Sustainability 14: 1780. DOI: https://doi.org/10.3390/su14031780.
17. Bauer Marek, Kinga Bauer.
2022. „Analysis of the Impact of the COVID-19 Pandemic on the Future of Public
Transport: Example of Warsaw”. Sustainability 14: 7268. DOI: https://doi.org/10.3390/su14127268.
18. Cieśla
Maria, Aleksander Sobota, Marianna Jacyna. 2020.
“Multi-Criteria Decision Making Process in Metropolitan Transport Means
Selection Based on the Sharing Mobility Idea”. Sustainability 12(17): 7231. DOI: https://doi.org/10.3390/su12177231.
19. Łabędzki Krzysztof. 2022. „Smart
Mobility – A Case Study of the Warsaw Metropolitan Area”. Organization Review 8(991): 29-38. DOI: https://doi.org/10.33141/po.2022.08.04.
20. City of Warsaw. “Report on city’s condition”. Available at: https://um.warszawa.pl/waw/strategia/raport-o-stanie-miasta.
21. The Public Transport Authority in Warsaw. „Statistical
information”. Available at: https://www.ztm.waw.pl/statystyki/.
22. Brown Robert Goodell.
1962. Smoothing, Forecasting and Prediction of Discrete Time Series,
Englewood Cliffs N.J.: Prentice-Hall.
23. Holt C. Charles. 1960. Planning
Production, Inventories, and Work Force. Englewood Cliffs: Prentice-Hall.
24. Lewis Colin. 1982. Industrial
and business forecasting methods: A practical guide to exponential smoothing
and curve fitting. London, Boston: Butterworth Scientific.
Received 06.03.2024; accepted in revised
form 05.05.2024
Scientific
Journal of Silesian University of Technology. Series Transport is licensed
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