Table 3 Factors improving the performance of the metro system in the study (https://www.intelligenttransport.com/transport-articles/118931/10-busiest-metro-systems/)

V1

Area/thousand

Square kilometer

(https://www.britannica.com/topic/list-of-the-total-areas-of-the-worlds-countries-dependencies-and-territories-2130540)

V2

Population

Million

(https://www.worldometers.info/world-population/population-by-country/)

V3

Gross annual income

Dollar/person

(https://www.worlddata.info/average-income.php)

V4

Number of stations

Number

(https://www.intelligenttransport.com/transport-articles/118931/10-busiest-metro-systems/)

V5

Distances between stations

Kilometers

(https://metro.fandom.com/wiki/List_of_rapid_transit_systems)

V6

Network length

Kilometers

(https://www.arcgis.com/apps/Cascade/index.html?appid=82e04b822de9437792a07f2309e6f4b6)

V7

Number of lines

Number

(https://metroautomation.org/wp-content/uploads/2019/05/Statistics-Brief-Metro-automation_final_web03.pdf)

V8

Travel time between stops

Minutes

(https://www.hindawi.com/journals/jat/2018/3690603/)

V9

Operational speed

Kilom/eterhour

(https://www.researchgate.net/publication/238001286_Study_on_the_maximum_operation_speeds_of_metro_trains_for_energy_saving_as_well_as_transport_efficiency_improvement)

V10

Ticket price

Dollars

(https://www.ubs.com/global/en/wealth-management/chief-investment-office/market-insights/2021/year-ahead.html)

V11

Flexibility

Percentage

(https://cms.uitp.org/wp/wp-content/uploads/2020/06/Statistics-Brief-Metro- automation_final_web03.pdf)

V12

Frequency

Minutes

(https://journals.sagepub.com/doi/abs/10.1177/0361198119845356)

V13

Integration with other systems

Percentage

(http://www.urbanrail.net/)

V14

Population density

Person per square kilometer

(https://en./List_of_countries_and_dependencies_by_population_density)

V15

Sustainability pollution and noise ratio

Percentage

(http://www.urbanrail.net/; http://mic-ro.com/metro)

V16

Accessibility

Percentage

(http://www.urbanrail.net/)

V17

Reliability

Percentage

V18

Safety from crime at stations/stops

Percentage

(https://www.essentialliving.co.uk/blog/the-worlds-best-subway-systems-revealed/; http://mic-ro.com/metro)

V19

Safety from crime on trains

Percentage

V20

Accident rate

Percentage

(https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Railway_safety_statistics_in_the_EU)

V21

Emergency exits

Percentage

(http://www.cityrailtransit.com/)

V22

Wheelchair accessible

Percentage

V23

Convenience

Hours of operation

(http://mic-ro.com/metro)

V24

Pet friendly

Percentage

(http://www.cityrailtransit.com/)

V25

Connectivity (WIFI)

Percentage

V26

Age of infrastructure

Years

(https://www.itf-oecd.org/sites/default/files/docs/dp201333_0.pdf)

V27

Comfort (bathrooms)

Percentage

(https://www.essentialliving.co.uk/blog/the-worlds-best-subway-systems-revealed/; http://mic-ro.com/metro)

V28

Comfort (air conditioning)

Percentage

(http://mic-ro.com/metro)