Regional public transport acessibility - case of Koroška region, Slovenia

Abstract

Public transport plays a major role in sustainable mobility planning. This is even more obvious on regional level, where distances are often too long for cycling, therefore public transport remains only viable sustainable travel mode. In the process of preparation of regional SUMP, evaluation of accessibility is one of crucial steps. However, accessibility measurement can be a challenging task. In Slovenia, there have been several studies measuring frequency and access to closest stop, ignoring travel speed and destinations that could be reached. However rapid increase in computing power, software development and availability of schedule data in GTFS format, opened an opportunity to evaluate accessibility more precisely. We performed an analysis for Koroška region in Slovenia. Accessibility was measured in both directions for all inhabited cells in a grid resolution of one hectare and central settlements of intermunicipal importance. The results of the analysis are important in terms of understanding how many citizens can access settlements of intermunicipal importance with public transport. This will serve as a baseline measure in regional SUMP preparation and will enable future iterations and comparisons. It also enables us to see the gaps in public transport supply and propose improvements. Method is universal and could be used for accessibility measurement in other regions and countries.

Full text

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8th INTERNATIONAL CONFERENCE
’’TOWARDS A HUMANE CITY‘‘
New Mobility Challenges
Novi Sad 11th and 12th November 2021
Simon Koblar, MSc1
E-mail: simonk@uirs.si
1 Urban Planning Institute of the Republic of Slovenia
REGIONAL PUBLIC TRANSPORT ACCESSIBILITY – CASE OF
KOROŠKA REGION, SLOVENIA
Key Words
Abstract
Accessibility
Public transport
SUMP
Koroška
Public transport plays a major role in sustainable mobility
planning. This is even more obvious on regional level, where
distances are often too long for cycling, therefore public
transport remains only viable sustainable travel mode. In the
process of preparation of regional SUMP, evaluation of
accessibility is one of crucial steps. However, accessibility
measurement can be a challenging task. In Slovenia, there
have been several studies measuring frequency and access to
closest stop, ignoring travel speed and destinations that could
be reached. However rapid increase in computing power,
software development and availability of schedule data in GTFS
format, opened an opportunity to evaluate accessibility more
precisely. We performed an analysis for Koroška region in
Slovenia. Accessibility was measured in both directions for all
inhabited cells in a grid resolution of one hectare and central
settlements of intermunicipal importance. The results of the
analysis are important in terms of understanding how many
citizens can access settlements of intermunicipal importance
with public transport. This will serve as a baseline measure in
regional SUMP preparation and will enable future iterations and
comparisons. It also enables us to see the gaps in public
transport supply and propose improvements. Method is
universal and could be used for accessibility measurement in
other regions and countries.

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1. INTRODUCTION
Public transport is one of the key sustainable mobility modes, especially on longer
distances. It also plays important part in preparation of regional SUMP. Important
step in planning public transport networks is measurement of accessibility that
current network provides. Different methods are used to measure accessibility [1],
[2]. In Slovenia several studies measured infrastructure-based accessibility [3]–[7].
Disadvantage of these type of indicators is focus on accessibility from the origin to
the public transit service, thus ignoring travel speed and reachable destinations [8].
To date, no study in Slovenia included public transport travel times in accessibility
measurements. In the paper we present measurement of accessibility to settlements
with at least intermunicipal importance by public transport, including access to transit
station, in-vehicle time, potential transfer time and walking to destination. We did not
choose to weight different parts of travel time as did some studies [9], because we
wanted a simple to understand indicator, that would be used as a baseline
measurement in the process of SUMP preparation and communication with
stakeholders.
2. METHODOLOGY
Paper focuses on measurement of accessibility with public transport to settlements
of at least intermunicipal importance in Koroška region, Slovenia. Koroška had
70,253 inhabitants in year 2019 [10]. Train and regional bus connections are
available. Settlements with at least intermunicipal importance were chosen because
they provide enough public and private services [11]. In Koroška this are Dravograd
and Ravne na Koroškem with intermunicipal importance and Slovenj Gradec with
regional importance. Population data for year 2019 in one hectare grid was retrieved
from Statistical office [12]. Public transport schedule data for intercity bus
connections and trains in GTFS format for year 2019 was provided by Ministry of
infrastructure. Pedestrian network was retrieved from OpenStreetMap [13]. Data
preparation and maps were created in QGIS open-source GIS software.
OpenTripPlanner [14] in combination with python script [15] was used to measure
travel times. Aggregation and statistical analysis of the travel times was performed
in Microsoft Access.
Travel times with public transport were measured in two directions between
inhabited grid cells to 58 settlements in Slovenia with at least intermunicipal
importance. Calculation for whole Slovenia was needed to enable comparison of
accessibility in Koroška to national average. Total walking distance was limited to
2000 m. Travel times to regional centres were calculated for departures between
6:00 and 8:00 and back from 14:00 and 16:00. We wanted to represent best case
scenario with flexible departure times and predicted that passengers would check
timetable before arriving at the stop. Therefore, we calculated departures every 15
minutes and subtracted initial wait time. For each origin-destination pair, shortest
travel time for each direction was used to calculate average travel time. Calculation
in both directions was needed, because in rural areas with low frequency, direct

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connection or connection with short transfer time is sometimes only available in one
direction.
3. RESULTS
In the process of SUMP preparation for Koroška region, travel times for Koroška
region were analysed in detail. Some statistics were also calculated on a national
level, which enabled us to put the result into the national context. Figure 1 shows
catchment areas of settlements with intermunicipal importance. Red colour
represent areas that are not accessible within 120 minutes of travel, or require more
than 2000 m of walking in each direction.
Figure 1. Catchment areas by public transport travel time
Accessibility to regional centre (Slovenj Gradec) is shown in table 1. Only inhabitants
of Koroška region are included.
Table 1. Number of inhabitants by travel times with public transport to Slovenj Gradec
travel time - minutes
inhabitants
share of inhabitants
up to 45
30.173
43 %
45–90
25.305
36 %
90–120
952
1 %
more than 120 or inaccessible
13.823
20 %
SUM
70.253
100 %
Table 2 shows travel times for inhabitants of Koroška region to three settlements in
Koroška with at least intermunicipal importance - Slovenj Gradec, Dravograd and
Ravne na Koroškem by public transport.

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Table 2. Accessibility of Koroška residents to closest intermunicipal centre by public
transport.
travel time - minutes
inhabitants
share of inhabitants
up to 45
53,836
77 %
45–90
4,206
6 %
90–120
192
0 %
more than 120 or inaccessible
12,019
17 %
SUM
70,253
100 %
Figure 2. Travel times with public transport to cities with at least intermunicipal importance
Figure 2 shows travel times for residents of Koroška with public transport to closest
settlement with at least intermunicipal importance. Note that closest centre can be
outside of Koroška region – see figure 1.
4. DISCUSSION
Slovenj Gradec as a regional center can be reached in 45 minutes by public transport
by 43 % of inhabitants of Koroška region, which is significantly lower than 77 % that
can reach centers with at least intermunicipal importance. Nevertheless 80 % of
Koroška residents can reach Sovenj Gradec by public transport. For services that
are not needed daily even a longer travel time is better than no accessibility. For
services needed daily, intermunicipal centers play a major role. Spatial distribution
of three intermunicipal centers is enabling public transport travel times under 45
minutes for 77 % of inhabitants, compared to 81 % on national level. Only 17 % of
inhabitants of Koroška region can’t reach intermunicipal centers. Considering rugged
terrain, accessibility to intermunicipal centres in Koroška is sufficient. All valleys and
major settlements have public transport connections available. Areas outside of

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valleys are so sparsely populated, that it is not viable to provide a regular public
transit. These areas could be served by on-demand service and/or integration of
school bus lines to regular public transport as feeder lines to existing bus and train
connections.
Public transport service areas are quite evenly distributed between Slovenj Gradec,
Ravne na Koroškem and Dravograd – see figure 1. This enables lower travel times
to closest center. Therefore, it is vitally important, that Dravograd and Ravne na
Koroškem provide enough public services and amenities. Municipality of Podvelka
in the eastern part of the region has better connections with Ruše, that lie in
Podravska region, which shows a discrepancy between traffic region and NUTS 3
region. Podvelka should therefore be included or at least considered in preparation
of SUMP for Podravska region.
Despite relatively good accessibility, there is still room for improvement. Especially
with train connection, which is outdated and does not enable sufficient speeds. But
train has a great potential, since it is independent of any traffic jams. Another
opportunity is cross border connection to Bleiburg, Austria, where Koralm railway
connecting Graz and Klagenfurt is under construction.
New infrastructure is also planned on Slovenian side, but in this case a new
motorway between Velenje and Slovenj Gradec is being built. This provides
opportunity to organize new express bus lines, but existing bus lines passing through
settlements should remain active to maintain current accessibility level.
5. CONCLUSION
Measurement of public transport travel times proved to be useful and easy to
understand indicator, which was used for the purpose of regional SUMP preparation.
Results showed that residents of Koroška have a relatively good connectivity to
regional centres, especially if we consider roughed terrain. However, this does not
ensure high usage of public transport since travel time with private car is still more
competitive. Our use case is also not representative for whole population, since we
measured public transport travel times only in a best-case scenario. Moreover, some
services are not available close to the city centers, and therefore require more
walking time. The question remains, how to organise public transport, once the new
expressway will be built. Settlements that lie by existing regional road should
maintain same level of service. New express lines that would use newly bult
expressway can reduce travel times for longer distance travel. However, travel time
with public transport will still be slower than by car due to lover maximum speed of
busses. Proposed methodology could be also used in other regions, since it relies
on standardized GTFS data and OpenStreetMap data which is available world-wide.
REFERENCES
[1] A. Malekzadeh and E. Chung, ‘A review of transit accessibility models:
Challenges in developing transit accessibility models’, International Journal

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354
of Sustainable Transportation, vol. 14, no. 10, pp. 733–748, Aug. 2020, doi:
10.1080/15568318.2019.1625087.
[2] K. T. Geurs and B. van Wee, ‘Accessibility evaluation of land-use and
transport strategies: review and research directions’, Journal of Transport
Geography, vol. 12, no. 2, pp. 127–140, Jun. 2004, doi:
10.1016/j.jtrangeo.2003.10.005.
[3] M. Gabrovec and D. Bole, ‘Dostopnost do avtobusnih postajališč’,
Geografski vestnik, vol. 78, no. 2, pp. 39–51, 2006.
[4] [4] J. Kozina, ‘Modeliranje prostorske dostopnosti do postajališč
javnega potniškega prometa v Ljubljani’, Geografski vestnik, vol. 82, pp. 97–
107, 2010.
[5] M. Gabrovec and N. Razpotnik Visković, ‘Dostopnost do javnega potniškega
prometa kot pogoj za socialno vključenost dijakov’, Geografski vestnik, vol.
90, no. 2, pp. 109–120, 2018.
[6] J. Tiran, L. Mladenovič, and S. Koblar, ‘Dostopnost do javnega potniškega
prometa v Ljubljani po metodi PTAL’, Geodetski vestnik, vol. 59, no. 4, pp.
723–735, 2015.
[7] A. Zavodnik Lamovšek, M. Čeh, and U. Košir, ‘Analiza dostopnosti
prebivalcev do javnih dejavnosti z medkrajevnim avtobusnim potniškim
prometom’, in Geografski informacijski sistemi v Sloveniji 2009-2010, D.
Perko and D. Perko, Eds. Ljubljana: Založba ZRC, 2010, pp. 251–260.
[Online]. Available: https://omp.zrc-sazu.si/zalozba/catalog/view
/649/2733/214-2
[8] S. Kaplan, D. Popoks, C. G. Prato, and A. (Avi) Ceder, ‘Using connectivity
for measuring equity in transit provision’, Journal of Transport Geography,
vol. 37, pp. 82–92, May 2014, doi: 10.1016/j.jtrangeo.2014.04.016.
[9] B. Tahmasbi and H. Haghshenas, ‘Public transport accessibility measure
based on weighted door to door travel time’, Computers, Environment and
Urban Systems, vol. 76, pp. 163–177, Jul. 2019, doi:
10.1016/j.compenvurbsys.2019.05.002.
[10] ‘SiStat’, Statistical Office of the Republic of Slovenia, 2019.
https://pxweb.stat.si/SiStat (accessed Mar. 18, 2020).
[11] J. Nared et al., ‘Central settlements in Slovenia in 2016’, Acta geographica
Slovenica, vol. 57, no. 2, Art. no. 2, Jan. 2017, doi: 10.3986/AGS.4606.
[12] ‘SURS STAGE’, SURS STAGE, 2019. https://gis.stat.si/ (accessed Aug. 26,
2019).
[13] OpenStreetMap’, OpenStreetMap, 2021. https://www.openstreetmap.org/
copyright (accessed Sep. 15, 2021).
[14] ‘OpenTripPlanner’. https://www.opentripplanner.org/ (accessed Aug. 05,
2019).
[15] R. H. M. Pereira and L. Grégoire, Tutorial with reproducible example to
estimate a travel time matrix using OpenTripPlanner and Python. 2019. doi:
10.5281/ZENODO.3242134.