Capacity of Zero-Emission Urban Public Transport

Abstract

The article explores the capacity of zero-emission urban public transport (PT) and proposes a standardised method for calculating it across different PT corridors (bus, tram, metro and urban railway). As the European Union (EU) tightens regulations on emissions, targeting also PT, cities are increasingly shifting to electric and hydrogen-powered vehicles. A significant challenge was the lack of a unified methodology to calculate the capacity of zero-emission vehicles, e.g., battery-powered buses carry fewer passengers than diesel ones due to weight restrictions. The article addresses this gap by creating capacity matrices for various vehicle types based on standardised assumptions. Vehicle capacity is calculated based on seating and standing space, with standing passenger space standardised to 0.2 m²/person (E Level of Service). A detailed rolling stock analysis shows how modern designs and floor layouts impact passenger space. Matrices were developed for each mode of transport, showing the number of transported passengers per hour depending on vehicle type and service frequency. The highest capacity is achieved by metro and urban railway systems (up to 95,000+ passengers/hour/direction), while buses offer the lowest (up to 7800 passengers/hour/direction). The authors recommend standardising calculation methods and integrating matrices into planning tools for urban PT corridors.

1. Introduction

Urban public transport (PT) in the world mainly consists of road and railway transport [1], in some situations supplemented by water (ferries), air (helicopters or drones in future) or cableway transport (cable cars). Road PT consists mainly of buses and trolleybuses, while railway transport is more complex, dividing into light rail (trams), urban rail (trains) and underground rail (metro) [2]; less popular are used railway transport types like monorails or funiculars. Currently, most urban cableways and railways are powered by electricity. Still, the rest of the vehicles are powered by combustion fuels, causing high pollutants, noise and greenhouse gas (GHG) emissions. Significant change started with road vehicle - buses, after introducing zero-emission vehicles such as electric or hydrogen buses [3]. The transformation of power sources also happens with ferries [4].

The importance of zero-emission public transport is highlighted by the European Commission, which has announced strategic documents for developing the European Union (EU). The European Green Deal (2019) set goal targets to reduce GHG emissions from transport by 55% by 2030 and 90% by 2050, compared to 1990 levels [5]. The Fit to 55 package from 2021 specifies more direct actions to reach the goal for 2030, i.e., promoting the introduction of zero-emission vehicles, energy efficiency and using renewable energy sources [6]. In January 2024, the Commission announced an agreement on tightening EU targets to reduce CO₂ emissions from new urban buses by 90% as of 2030 and to be only zero-emission from 2035 [7]. Nevertheless, effective public transport should also lead to a reduction in car dependency [8].

As European targets are tightening to introduce zero-emission public transport, nowadays, there is a lack of unified calculation methods to determine the capacity of the public transport corridor cross-sections. A wide range of zero-emission urban PT transport modes should be considered. Earlier adopted guidelines covered calculations only for diesel buses. Zero-emission buses, carrying heavy batteries on board, can generally board fewer passengers than diesel ones. Moreover, rolling stock manufacturers adopt different values of standing area conversion factors in their technical specifications, so public transport organisers, by using them, are miscalculating absolute values. The calculating factors must be unified according to one methodology, or the capacity matrix should include their possible variety.

While the previous research has predominantly focused on the environmental benefits, economic viability and technological characteristics of zero-emission vehicles, particularly battery-electric and hydrogen-powered buses, comparatively little attention has been paid to their operational capacity and ability to deliver high-frequency services in complex urban environments. This study aims to create unified matrices of the most popular urban zero-emission PT modes of transport: buses, trams, trains and metros; for scientists and designers to analyse the capacity of PT corridors. The same calculating factors regarding passenger space compartments were adopted, which is a novelty in PT science because scientists earlier adopted values based on vehicle manufacturers’ assumptions. The construction of such a matrix will shorten the design time and allow for efficient assessment of the potential capacity of the PT corridor. Other modes of transport, such as monorail or cable car, were not considered because of their high specialisation, low usage ratio and lack of universal vehicle types used worldwide.

2. Literature Review

The review started with the reasons behind the zero-emission urban PT and goals set at various levels of government. Then, aspects of the capacity calculations in PT are presented. The last section of the literature review covers the currently used norms for vehicle capacity calculations and their feasibility in reality.

2.1. Zero-Emission Urban Public Transport

The main challenge indicated by researchers in the reviewed literature is achieving a zero-emission fleet of buses, while the railway fleet is already mainly electric. Prognosis conducted in 2020 demonstrated that by 2050, only four of the EU countries will be able to reach a 95% share of zero-emission buses in the city bus transport fleets [9]. There are smaller countries like Portugal where the bus fleet replacement follows the criteria of the complete decarbonisation of the bus fleet even by 2034, considering the maximum age of 14 years per vehicle [10]. In the case of cities, Milan in Italy plans to reach a 100% electric fleet in 2030 or even shorten that period to 2026 to prepare for the Winter Olympic Games [11]. On the other hand, a study for Hong Kong showed that only 66% of the bus fleet would be composed of zero-emission buses by 2050 [12].

In densely populated metropolitan areas with high congestion and pollution levels, the lower running costs, high mileage (greater than 70,000 km annually) and reduced external costs of battery electric buses make them more suitable than in smaller urban areas. The economic barriers of high initial costs and shorter operating range after a single charge are not sufficiently offset by external cost reductions in those areas [13]. Poland follows that rule, where zero-emission buses are more common in large cities, are highly positioned in the urban hierarchy, are economically sound, have a well-developed tertiary economy and have high human capital [14].

Cities introducing zero-emission transport should analyse and specify charging infrastructure, fleet size, technology type, staff training and stakeholder collaboration [15]. Researchers were studying different charging strategies to find the most effective one, reducing the operational costs of a zero-emission bus fleet [16]. Analysis showed that deployment of a mixed fleet can lead to financial benefits. A mix of overnight charging and opportunity charging with supercapacitors was optimal for the investigated bus network in Graz, Austria [17]. Network building features and the charging infrastructure’s location are crucial for the adoption of zero-emission buses [18].

Transition to zero-emission buses faces not only barriers like range and costs but also institutional, regulative, normative and cognitive ones [19]. Government support improves zero-emission transport efficiency more quickly in a brief period. At the same time, charging infrastructure, affordable electricity tariffs and access to electric minibuses are more effective in stimulating transport efficiency over a more extended period [20]. Some transit agencies are exploring public–private partnerships as a potential solution for rapid development, as they help fund, build and maintain the necessary infrastructure while managing risks and operational demands [21].

The economic feasibility of transitioning to zero-emission buses highlights the long-term benefits for urban transport systems. The cost–benefit analysis (CBA) method is mainly used in connection with EU funding [22]. The long-term benefits for urban transport systems include significant environmental improvements, economic efficiency, enhanced public health, increased sustainability and compliance with government regulations [23]. These effects are achievable when combined with efforts to increase the renewable energy in the energy mix [24]. On the other hand, there is a lack of studies showing the differences between the capacity of zero-emission and diesel buses, which is crucial for this research.

2.2. Capacity of Urban Public Transport

Public transport capacity is mainly designated for a given PT line or corridor as the maximum number of passengers per time unit (especially hour) and direction of movement that can be transported by a specific mode of transport on a selected cross-section, assuming PT frequency of operation and the vehicle class used (its capacity) [25]. Over the years, capacity matrices have changed because of the advances in the traffic control systems and modernisation of the vehicle fleets.

PT capacity can be broken down into four subsystems connected with the passenger, the vehicle, the station, and the line. Capacity calculations can cover seven broad categories, namely: (i) the vehicle capacity on a given infrastructure; (ii) the vehicles fleet capacity; (iii) the passenger capacity of a vehicle; (iv) the passenger capacity of a route; (v) the passenger capacity of a station; (vi) the vehicle storage and movement capacity of a station; (vii) the capacity of a station for interface with personal transport modes [26].

Capacity can be calculated for a station (stops), intersections and PT transit ways. The time spent stopping at the station is crucial to calculating the capacity, especially when passengers alight and leave the vehicles. The essential time is spent at intersections waiting to pass the right-of-way or at a red signal on traffic lights. The smallest calculated capacity from all the elements in the corridor is considered the PT corridor capacity. Generalised values for the corridors consider the maximum throughput of vehicles.

In some concepts, PT capacity determines the PT level of service (LOS), similar to the LOS concept with road traffic [27]. Further studies specified the newsvendor cost model in the optimisation model, where overcrowding is treated as a shortage and empty seats as surplus [28]. Maximum (theoretical) and design (achievable, practical) capacity should be distinguished. The maximum capacity relates to the crush load conditions and its value is unstable and unreliable, so it is not considered further in the article. At the same time, the design capacity reflects the service providing an acceptable PT level of service [29].

Estimating correlations among capacity, block section length, timetable and operational plan is conceived as a basis to provide guidelines to design new urban railways or to evaluate possible reliability effects of actions on block sections (often with changes on the adopted signalling) or timetables [30].

The location of the bus corridor and the setting of bus lanes are closely related to passenger flow. The one-way traffic on most roads identified as bus corridors has a capacity greater than 6671 people/hour. When the passenger flow reaches 15,551 people/h, a new bus road with an independent right of way should be built [31]. Models of dwell time between buses were also constructed [32]. Scientists calculated a number of bus berths to optimally service a high volume of bus arrivals [32]. Optimisation of the feeder bus networks were also researched [33]. To calculate bus rapid transit (BRT) corridor capacity, the Institute for Transportation and Development Policy, a non-governmental non-profit organisation focusing on developing BRT systems, created an online guidebook [34].

Railway systems are known for their ability to transport up to 100,000 passengers per track per hour per direction. In some cases, integrated bus systems, like BRT, are viewed as an affordable, cost-effective alternative to them. The capacities of these systems, with a maximum practical capacity of about 25,000–35,000 for two lanes, 10,000–15,000 for one, do not exceed the number of passengers carried on many urban rail transit systems [35].

A comprehensive literature review from 1990–2020 indicated that the researchers’ experiments generally contribute to the rollout of low-emission vehicle technologies and BRT systems, followed by the development of other avoid–shift–improve measures [36].

Most studies consider actions to increase the effectiveness of PT in different circumstances. Cats and Jenelius propose and demonstrate a methodology for evaluating the effectiveness of a strategic increase in capacity on alternative PT links to mitigate the impact of unexpected network disruptions [37]. Another idea for PT optimisation is a collaborative urban transport service, which could both move goods and passengers to decrease the economic deficit in PT. Integrating urban logistics into the PT could have potential efficiency gains in specific periods of non-peak or low ridership hours [38]. It is an interesting idea for little buses servicing lines only during rush hours, so they are used mainly for 6–8 h per working day, while regular daily service is for around 20 h, and rush-hour buses are standing in the depot during weekends. Furthermore, the introduction of autonomous public transport vehicles can increase capacity and efficiency of PT corridors because of the lack of drivers, reduction of vehicles’ (drivers) reaction time and space needed for driver cabin [39].

Scientists also established a multi-objective optimisation model for the capacity allocation of an urban rail transit network based on multi-source data [40].

Eric C. Bruun, in the book “Better public transit systems: analysing investments and performance”, recommends some actions related to the capacity of the public transport system. Considerations should cover both seating and standing spaces in vehicle capacity. According to the infrastructure, high-capacity operations could be provided on dedicated lanes or separated tracks from road traffic. In the case of PT stops, advanced ticketing solutions can reduce boarding times and increase the throughput of passengers at stops [41].

2.3. Norms to Calculate the Number of Passengers in Vehicles

The vehicle’s capacity is fundamental to calculating the PT corridor’s capacity. Crowd science can be applied to understand how to specify the vehicle’s capacity. The method uses static crowd density, the number of people per m². Its value for standing spaces (such as in urban PT vehicles) should be between 0 and 5 people per m² for a standardised person. Still, the demographics of society could differ from that value [42].

The basis for determining public transport capacity in Poland is the Regulation of the Minister of Infrastructure of 2 March 2011 on the technical conditions of trams and trolleybuses and the scope of their necessary equipment. It specifies the permissible vehicle capacity as the sum of seats and standing places, assuming that 0.2 m² of area falls on one standing person (meaning 5 people per 1 m²) [43]. Only the area available for standing people should be assumed to calculate the number of standing places. Assumed values are used for E LOS in related research, while higher LOS starts from 0.35 m²/passenger for D LOS, 0.51 m²/passenger for C LOS, etc. F LOS is considered a crush load, and the space for one standing passenger is lower than 0.20 m² [44].

The requirements for buses are included in the Regulation of the Minister of Infrastructure of 31 December 2002 on the technical conditions of vehicles and the scope of their necessary equipment (consolidated text of 27 October 2016, with subsequent amendments). Paragraph 17, Section 1 of the Regulation states, “the number of passenger places for seated and standing passengers should be established so that the permissible total weight of the bus is not exceeded”. This is the only paragraph of this Regulation that limits the number of passenger places for buses used in public transport, which are not school buses [45]. This, therefore, leaves the rolling stock manufacturers open to use in the declarations of the maximum number of passengers. For example, in the case of 18-metre-long articulated buses, the maximum number of passengers is 120 to 174. It is also related to the power source and engine; for example, the same model of bus with a diesel engine takes on board 174 passengers [45], the hybrid version 142 [46] and the electric one–120 [46]. However, such a significant difference does not result from a significantly different area of the passenger space. Still, from technical requirements related to permissible gross vehicle weight, the total of the vehicle’s weight (or combination of vehicles), including its load when stationary and ready for the road, is declared permissible by the country’s competent registration authority. This includes the weight of the driver and the maximum number of persons permitted to be carried [47]. Assuming 17.4 m² of area for standing passengers in this type of vehicle (18 m long and 2.55 m wide, and the standing passenger area accounting for 38% of the vehicle area), this means between 0.1 and 0.15 m² of area per standing passenger.

The Warsaw Metro in its 2017 specification for the delivery of 36 + 8 six-car electric multiple units assumed the calculation of the parameters of a train with a nominal load for a density of 7 passengers/m² and all seats occupied (implicitly seated) [48]. In this case, 0.14 m² of area per standing passenger was assumed. In the case of railway vehicles, the requirements are again based on the permissible vehicle load. The specification for new electric multiple units for the Warsaw Fast Urban Railway (SKM) includes the following entry: “D7 (parameter) refers to the structural strength of the vehicle, i.e., the load should be >500 kg/m², while the entries in points L2 and L3 (parameters) concern the methodology for calculating the filling factor, which assumes 6.7 people/m² (i.e., 469 kg/m²) [49], which means that the total capacity should be calculated as the sum of seats and the area for standing people.” This provision states that the requirements for railway vehicles assume a minimum area of 0.15 m² per standing passenger.

The above analysis shows that while the basis for determining the vehicle capacity in the case of trams and trolleybuses is the standard of 0.2 m², in the case of buses, metro trains and railway vehicles, the basis is the permissible total weight (gross vehicle weight) of the vehicles (and consequently between 0.1 and 0.15 m² of area per passenger). Gross vehicle limitations do not influence the passenger behaviour and use of the passenger compartment. However, regardless of the conditions in which passengers will travel and taking into account the lack of awareness of passengers about the limitations resulting from the vehicle’s weight, the number of seats and the area of the passenger space for standing determines the number of passengers who will travel in the vehicle. Drivers in crowded urban PT also do not check how many passengers are on board and do not ask people to leave the vehicle when it is overcrowded. So, the number of permitted passengers on board is exceeded. From the scientific point of view, the gross vehicle weight limitation does not influence the number of passengers travelling on board. Due to such a range of manufacturers’ assumptions and the requirements of public transport operators, the most restrictive requirement, relating to the standing area, i.e., 0.2 m² of area per standing place, was adopted as the “standard” for further calculations, contributing for E LOS, which is the biggest acceptable vehicle capacity.

3. Method

The method outlined in the schematic (Figure 1) systematically assesses the capacity of urban zero-emission PT systems by first analysing the characteristics of four transportation modes: buses/trolleybuses, trams, metros and urban railways. The interior design and spatial layouts, including seating arrangements and standing areas, were examined. The next step involved calculating the capacity of a single vehicle based on these characteristics and designs, considering factors like seat layout and standing capacity. Finally, the method extends to the calculation of corridor capacities, using vehicle capacities and service frequency to determine the corridor capacity of the transport mode.

3.1. Characteristics of Modern Rolling Stock

Public transport rolling stock has significantly changed over the past 25 years, especially regarding buses, trams and trains. High-floor (HF) vehicles have been replaced with low-floor (LF) ones, altering the interior layout. Elements of the vehicle’s chassis, previously hidden in the bodywork below passenger compartment floor level, have started interfering with the passenger space. New features have also appeared, such as ticket machines and barrier-free designated areas for disabled passengers or mothers with children in strollers, which are now placed in a space previously used for standing. Those elements have reduced vehicle capacity.

3.1.1. Bus and Trolleybus

Buses used in Poland and Eastern Europe before the LF vehicle era, between 1970 and the 2000s, were mainly Hungarian HF 11-m-long Ikarus 260 [50] and articulated 16.5-m-long Ikarus 280 [50] buses with 22 and 35 sitting places, respectively, accommodating 100 and 160 passengers in total. In practice, they often carried more passengers, especially during peak hours. Such practices created dangerous situations, such as the possibility of fainting or difficulties with exiting the bus.

LF buses entering service in the 2000s changed the arrangement of the engine compartment space. The engine was positioned horizontally under the last row of seats in older designs. The engine is usually placed vertically in newer designs, removing this space from passenger use. The introduction of electric buses also complicated this part; some engines are not located in a vertical tower at the end of the vehicle but in the vehicle’s axles. Some packets of batteries are also located not only on the roof of a vehicle but also near the axles. Managing the space above the wheel arches in LF or LE buses is also more challenging. Part of the space related to the vehicle’s front axle is used as a seat backrest or a small luggage area. It is easier to utilise space in other vehicle sections, where seats are usually placed on raised platforms to maximise the available area. These are the two main elements related to the structure of the vehicle.

Depending on the transport network, the driver’s cabin design (whether open, semi-open or closed) and the number of standing zones, large areas designated exclusively for standing passengers, generally located opposite the middle doors (two in standard buses or three in articulated buses), can affect available passenger space. At the same time, in addition to LF buses, low-entry (LE) vehicles operate in public transport. Nowadays, these are purchased especially in the short version of buses: between 6 and 9 m in length. Regarding space utilisation, their design optimises passenger capacity—the floor level gradually rises behind the second doors to maximise seating arrangements. At the same time, the engine and batteries are placed horizontally, ensuring it does not limit the space available to passengers. The available space for passengers can be increased by properly mounting seats and barriers, as well as by using doors that open outward, as seen in the newest Solaris Urbino (SU) or Solaris Trollino (ST) IV generation buses and trolleybuses, the most popular model of currently used urban bus and trolleybus in Poland. This helps maximise the space available for passengers, increasing the bus’s capacity and ensuring safe driving conditions compared to the older models.

Nowadays, the primary classification of buses used in urban transport is based on their length and is called class division. Midi, Maxi, Mega and Giga single-unit or articulated buses are the basis. For analysis purposes, the bus models produced by Solaris, the leading manufacturer of electric buses in Poland, were considered: Urbino 9 LE electric; Urbino 12 LF electric; Urbino 15 LE electric; Urbino 18 LF electric and Trollino 24 LF (trolleybus, giga bus, double-articulated) [51].

Differences in the interior design of the trolleybus and electric bus (12-m, 15-m and 18-m long) are insignificant and depend on the vehicle configuration and specific order of the PT fleet operator. Both modern vehicles of those types are equipped with electric engines and battery packages. The configuration of an electric bus with a small battery pack (energy of 90–150 kWh) is comparable to that of a trolleybus with a bigger battery pack, so the difference in the interior arrangement is small. The biggest space is in trolleybuses without battery packs, which nowadays are not commissioned because of their lack of elasticity in traffic without connection to the wire network. The difference could be of 3–5 passengers in the vehicle, which is highly connected with specific interior design but is not significant for comparison of different modes of transport (especially with trams, metros and urban railways). That was the reason for connecting the matrices for both types of vehicles.

3.1.2. Tram

Nowadays, there are distinguished single-tramcars and multi-section vehicles in tram transportation. Tramcars are coupled into compositions (in Poland, a maximum of three-car sets are used), whereas multi-section vehicles operate mainly individually. As a result, tram lengths can be classified into five main groups: 13.5-m tramcars (produced before the 2000s) and multi-section trams of approximately 20, 30, 42 and 54 m in length (modern LF trams). For analysis purposes, the most common tram models used in Poland were considered for the first four categories (Konstal 105Na and Pesa Bydgoszcz vehicles) [52], while for the longest category, Siemens Combino trams operating in Budapest (there are no 54-m-long trams in exploitation in Poland). A significant drawback of the trams currently operating in Poland is their width (2.35–2.40 m), which is narrower than buses (2.55 m) and often prevents using a 2 + 2 seating configuration. Capacity is also influenced by whether the tram is one or bidirectional. The vehicle must have one or two driver cabins at the vehicle’s ends. That means lower passenger space and capacity [53].

In LF trams, the primary limitation of passenger space is caused by bogies and engines, components of the vehicle’s undercarriage that encroach into the body space. Seats are usually installed on their covers and luggage shelves due to the lack of space for standing passengers. Traditional tramcar designs are also being ordered less frequently in favour of articulated (multi-section) constructions. However, their advantage lies in providing a larger usable area for passengers, as they can stand in the articulated sections between segments (seg). A standard five-section, 30-m-long tram (e.g., Pesa 120Na Swing) is connected by four articulation joints, offering additional standing space. However, due to the construction of the articulation, this space is not fully available across the entire width of the tram.

3.1.3. Metro

To maximise passenger capacity, metro trains are now articulated and single-space units. The most common configurations in metro systems include 2-, 3-, 4-, 5-, 6- and 8-car sets, each of which is approximately 20 m long. Depending on the system, metro train widths can vary. In Warsaw (Poland), they are 2.74 m wide, making them wider than the buses and trams used in the country.

The operation of single-space train sets increases the area available for passengers, who can travel standing in the articulation sections, similar to trams. The construction of modern metro cars (e.g., Siemens Inspiro) has also been made lighter than their predecessors. Compared to other modes of transport, one of the most distinctive features, especially in Warsaw, is the seating arrangement, with seats positioned sideways to the direction of travel and back against the vehicle’s side walls. This configuration maximises standing space [54].

3.1.4. Urban Railway

Various train sets can be used in urban transport, including those specifically designed for city railway systems (e.g., Warsaw’s Fast Urban Railway–SKM) [55], suburban railway (e.g., Lodz Agglomeration Railway–ŁKA) [56], or regional railway (e.g., Masovian Railways–KM) [57]. All the above railway systems often mix in the urban zones. Like metro trains, modern vehicles are typically multiple units consisting of several interconnected cars. Their construction usually includes 1 to 8 sections. In railway transport, these multiple units are often coupled in multiple traction, with a maximum of three basic units combined. In Poland, railway rolling stock is the widest among vehicles used in urban transport, measuring 2.82 m in width.

Compared to older rolling stock, where the EN57 was the most common train in Poland, modern designs no longer feature separated entrance areas divided by walls and doors from passenger compartments. Many train sets are open planned, with only windbreak partitions partially separating the passenger area from the entrances. As a result, these trains offer more standing space for passengers. Typically, railway seating arrangements follow a 2 + 2 configuration, either facing or opposing the direction of travel. However, some areas include foldable seats positioned sideways. This is especially common in passageways near restrooms or designated spaces for wheelchairs, strollers, or bicycles. In the absence of such elements, standing passengers often use these areas.

3.2. Methodics-Transport Capacity Matrix

The capacity matrix of urban transport vehicles was calculated using Equation (1),

$$x={\displaystyle \frac{60}{t}}·vc$$

(1)

where

x is corridor transport capacity [passengers/h/direction],

t is service frequency [min],

vc is capacity of vehicles operating the route [passengers].

3.2.1. Adopted Set of Service Frequencies

The following set of service frequencies was adopted for public transport corridors:

t ɛ [0.5; 1; 2; 3; 5; 7.5; 10; 12; 15; 20; 30; 60] [min].

This set includes the most typical values used in timetable planning, following the principle of maintaining regular service frequencies (cyclic scheduling). The rule ensures that the number 60 (representing minutes in an hour) is divisible by the frequency value, resulting in a whole number of trips per hour.

Most of these frequencies can be achieved even on a single transit line; the exceptions are 0.5- and 1-min frequencies, which assume the coexistence of multiple lines within the transport corridor. By overlaying departure schedules, departures can be synchronised to occur approximately every 1 min. For the capacity matrix calculations, it was also assumed that such high frequencies are not feasible within the railway network.

3.2.2. Determination of Vehicle Capacity

The vehicle capacity was calculated based on the number of seats and the available standing area. An interior layout was obtained for each vehicle model, and the space was then divided into squares of 0.01 m² each. Subsequently, the squares corresponding to the standing passenger area were identified (the example includes Figure 2).

The normative number of passengers standing in the vehicle was calculated based on the ratio of marked to unmarked squares, the vehicle surface, and the standard of 5 people per m². The diagrams also marked the seats, which were also counted. The sum of both types of seats allowed to determine the total number of passengers for each vehicle (see

Table 1. The normative vehicle capacity calculated based on the vehicle interior and passenger space allocation.

Type	Area [m2]	Sitting Places [People]	Standing Places [People]	Capacity [People]	Density [People/m2]	No. of Points in the Calculation Matrix	Percentage of Standing Area
Electric bus/Trolleybus
Solaris Urbino 9 LE electric	22.7	27	31	58	2.54	2205	27%
Solaris Urbino 12 LF electric	30.6	28	50	78	2.56	3060	33%
Solaris Urbino 15 LE electric	37.8	57	53	110	2.90	3780	28%
Solaris Urbino 18 LF electric	45.9	42	88	130	2.82	4590	38%
Solaris Trollino 24 LF	63.0	58	117	175	2.78	6300	37%
Tram
Konstal 105Na HF	32.4	20	80	100	3.09	3240	50%
Pesa 20 m LF	45.6	25	100	125	2.74	4560	44%
Pesa 30 m LF	70.7	40	175	215	3.05	7074	50%
Pesa 43 m LF	102.7	93	207	300	2.92	10,272	40%
Siemens Combino 54 m LF	129.6	62	348	410	3.16	12,960	54%
Metro
Metro steering seg	55.1	34	159	193	3.50	5510	58%
Metro middle seg	53.1	44	156	200	3.77	5310	59%
Metro 2 seg	110.1	68	317	385	3.50	-	-
Metro 3 seg	163.3	112	473	585	3.58	-	-
Metro 4 seg	216.5	156	629	785	3.63	-	-
Metro 5 seg	269.6	200	785	985	3.65	-	-
Metro 6 seg	322.8	244	940	1184	3.67	-	-
Metro 8 seg	429.1	332	1252	1584	3.69	-	-
Train (DMC * or EMU **)
Pesa DMC * (1 seg)	79.2	58	104	162	2.04	7868	26%
Stadler Flirt ** (2 s.)	128.9	100	168	268	2.08	12,796	26%
Stadler Flirt ** (3 seg)	178.2	154	252	406	2.28	17,696	28%
Stadler Flirt ** (4 seg)	227.6	210	332	542	2.38	22,596	29%
Stadler Flirt ** (5 seg)	276.9	269	421	690	2.49	27,496	30%
Stadler Flirt ** (6 seg)	300.6	300	425	725	2.41	29,848	28%
Stadler Flirt ** (8 seg)	423.6	377	551	928	2.19	42,056	26%
Stadler Flirt ** (2 × 5 seg)	553.8	538	841	1380	2.49	54,992	30%

Source: own study. * DMC–diesel motor coach. ** EMU–electric multiple unit.

). The table also converts the capacity into standard passenger density.

The capacity of buses ranges from 58 to 175 passengers, trams from 100 to 410, metro sets from 385 to 1584 and trains from 162 to 1379. The highest number of seats is in trains (58–538) and the lowest in trams (20–62) and buses (27–58). The highest passenger density was calculated for metro sets (3.50–3.69 people/m²) and the lowest for trains (2.04–2.49 people/m²). This parameter strictly relates to the percentage of standing area, and the vehicle’s capacity is the lowest when seats are configured in a 2 + 2 set and the highest when 1 + 1 seats are opposite to the vehicle’s sides. The capacity of vehicles was used to calculate the modes of transport capacity matrices.

The normative vehicle capacity was calculated for E level of service (LOS, standard design capacity, 0.2 people/m²) and 2 higher levels: D with 0.36 people/m² and C with 0.51 people/m². Values for all vehicles are covered in

Table 2. The normative vehicle design capacity calculated for C-E LOS.

Type	E LOS Capacity [People]	E LOS Density [People/m2]	D LOS Capacity [People]	D LOS Density [People/m2]	C LOS Capacity [People]	C LOS Density [People/m2]
Electric bus/Trolleybus
Solaris Urbino 9 LE electric	58	2.54	44	1.94	39	1.72
Solaris Urbino 12 LF electric	78	2.56	56	1.83	48	1.56
Solaris Urbino 15 LE electric	110	2.90	86	2.28	78	2.05
Solaris Urbino 18 LF electric	130	2.82	91	1.98	76	1.66
Solaris Trollino 24 LF	175	2.78	123	1.95	104	1.65
Tram
Konstal 105Na HF	100	3.09	65	1.99	51	1.59
Pesa 20 m LF	125	2.74	81	1.77	64	1.41
Pesa 30 m LF	215	3.05	137	1.94	109	1.54
Pesa 43 m LF	300	2.92	208	2.02	174	1.69
Siemens Combino 54 m LF	410	3.16	255	1.97	198	1.53
Metro
Metro steering seg	193	3.50	122	2.22	96	1.75
Metro middle seg	200	3.77	131	2.46	105	1.98
Metro 2 seg	385	3.50	244	2.22	192	1.75
Metro 3 seg	585	3.58	375	2.30	298	1.82
Metro 4 seg	785	3.63	505	2.33	403	1.86
Metro 5 seg	985	3.65	636	2,36	508	1.88
Metro 6 seg	1184	3.67	766	2.37	613	1.90
Metro 8 seg	1584	3.69	1028	2.39	823	1.92
Train (DMC * or EMU **)
Pesa DMC * (1 seg)	162	2.04	116	1.46	99	1.25
Stadler Flirt ** (2 s.)	268	2.08	193	1.50	166	1.29
Stadler Flirt ** (3 seg)	406	2.28	294	1.65	253	1.42
Stadler Flirt ** (4 seg)	542	2.38	394	1.73	340	1.49
Stadler Flirt ** (5 seg)	690	2.49	503	1.82	434	1.57
Stadler Flirt ** (6 seg)	725	2.41	536	1.78	467	1.55
Stadler Flirt ** (8 seg)	928	2.19	683	1.61	593	1.40
Stadler Flirt ** (2 × 5 seg)	1380	2.49	1005	1.82	868	1.57

Source: own study. * DMC—diesel motor coach. ** EMU—electric multiple unit.

. Consequently, at higher LOS, the design capacity of vehicles is lower.

4. Determination of the Transport Capacity Matrix

The matrix was developed for four transport modes: buses/trolleybuses, trams, metro and urban (agglomeration) railway. Equation (1) was used for its determination. Frames with a transport capacity of up to 499 passengers/hour/direction are marked in red, 500–1499 in orange, 1500–4999 in yellow, 5000–24,999 in light green, 25,000–49,999 in dark green and 50,000 and above in blue, while grey indicates values that are unreachable due to the technical limitations of railway transport traffic operations.

4.1. Bus/Trolleybus Transport Capacity Matrix

The first matrix determined was for bus transport capacity (see

Table 3. Bus and trolleybus transport design capacity matrix [passengers/h/direction].

		Electric Bus/Trolleybus
Vehicle Class Vehicle Model		Midi SU 9LE	Maxi SU 12LF	Mega SU 15LE	Mega SU 18LF	Giga ST 24LF
Dimensions [l × w in m]		9.25 × 2.45	12.0 × 2.55	14.9 × 2.55	18.0 × 2.55	24.7 × 2.55
Capacity [pas.]		58	78	110	130	175
Frequency [min]	0.5	6960	9360	13,200	15,600	21,000
	1	3480	4680	6600	7800	10,500
	2	1740	2340	3300	3900	5250
	3	1160	1560	2200	2600	3500
	5	696	936	1320	1560	2100
	7.5	464	624	880	1040	1400
	10	348	468	660	780	1050
	12	290	390	550	650	875
	15	232	312	440	520	700
	20	174	234	330	390	525
	30	116	156	220	260	350
	60	58	78	110	130	175

Source: own study.

). The lowest transport capacity characterises bus transport corridors. The maximum value of 21,000 passengers per hour per direction may be difficult to achieve in a corridor with traffic signals (often operating in a 2-min cycle), double-articulated giga buses, and double bus stops. The corridor must handle 120 bus trips per hour in such a case. It would be possible to achieve this on some highly advanced BRT corridors. In practice, an achievable value in Poland is 7800 passengers/h/direction, assuming operation with 18-m-long buses and a total line frequency in the corridor of one minute.

The most standardised bus is 12 m long, and bus lines in urban areas in Europe primarily operate with a frequency of 10–15 min, which means the corridor capacity of 312–468 passengers/h/direction. The top frequency of a single line is in most PT systems 3 min, which means the line’s capacity is up to 1160–3500 passengers/h/direction. However, multiple lines are often serviced on the bus transport corridors. By calculating their combination, the study’s 7800 passengers/h/direction for high-level bus operation (18-m-long, articulated bus with frequency of 1 min at the corridor) fits very well into the expected typical range from the literature review. The theoretical 21,000 passengers/h/direction aligns with top BRT corridors. Still, it would require exceptional conditions (double stops, signal priority or collision-free routes) and is reached at PT BRT corridors in China, Latin America countries and Türkiye. The lowest expected frequency for the bus service in urban areas is 60 min. However, there are still areas with even lower frequency, e.g., 120 or 180 min lines with such a timetable are mainly social or school connections, and there is no need to determine the corridor capacity of such a service.

4.2. Tram Transport Capacity Matrix

The following determined matrix was for tram transport capacity (see

Table 4. Tram transport design capacity matrix [pas./h/direction].

		Tram
Vehicle Class Vehicle Model		Carriage 105Na	20-m Pesa 20 m	30-m Pesa 30 m	40-m Pesa 43 m	50-m Combino 54 m
Dimensions [l × w]		13.5 × 2.4	19.4 × 2.35	30.1 × 2.35	42.8 × 2.4	54.0 × 2.4
Capacity [pas.]		100	125	215	300	410
Frequency [min]	0.5	12,000	15,000	25,800	36,000	49,200
	1	6000	7500	12,900	18,000	24,600
	2	3000	3750	6450	9000	12,300
	3	2000	2500	4300	6000	8200
	5	1200	1500	2580	3600	4920
	7.5	800	1000	1720	2400	3280
	10	600	750	1290	1800	2460
	12	500	625	1075	1500	2050
	15	400	500	860	1200	1640
	20	300	375	645	900	1230
	30	200	250	430	600	820
	60	100	125	215	300	410

Source: own study.

). Tram transport corridors are characterised by medium transport capacity. The maximum value of 49,200 passengers per hour per direction is technically impossible to achieve in a typical tram corridor due to the location of stops before intersections with traffic signals, the servicing of trams once per cycle and double stops.

Budapest (Hungary) lines 4 and 6 operate the same track corridor and are serviced by Combino 54 m trams. They run at a 2-min frequency, achieving a corridor capacity of 12,300 passengers per hour per direction. Under Polish conditions, where 30-m-long trams dominate, a practically achievable transport capacity may be 12,900 passengers per hour per direction in a corridor served by trams every 1 min, meaning 2 trams coming to the double stop at once because of the basic traffic lights cycle length of 2 min. Traffic lights must be considered a bottleneck of tram networks, and there are no tram networks in Poland without any traffic lights.

Tram service in most networks relates to lines of frequency at least 20–30 min up to 2–3 min. The study’s 12,900 passengers/hour/direction for standard tram operation is consistent with real-world operations (e.g., Warsaw 12,900 or Budapest 12,300 passengers/h/direction; general capacity typically around 8000–16,000 passengers/h/direction). Europe’s most common tram type is a 30-m-long tram, so the standard capacities vary from 430 to 12,900 passengers/h/direction. On top service corridors multiple lines provide connections at the same corridor, meaning that trams can operate with maximum frequency of 1 min, but in the reality of highly congested cities, even though the timetable shows departures every minute, the most common cycle time of traffic lights limit it to up to 2 min with a departure of the two trams at the same time. The maximum theoretical number (49,200 passengers/h/direction) is much higher than real cases, mainly because of real-world operational bottlenecks of tram networks (traffic signals, stop platforms capacity).

4.3. Metro Transport Capacity Matrix

The following determined matrix was for metro transport capacity (see

Table 5. Metro transport design capacity matrix [pas./h/direction].

		Metro
Vehicle Class		2-Segment	3-Segment	4-Segment	5-Segment	6-Segment	8-Segment
Dimensions [l × w]		40.2 × 2.74	59.6 × 2.74	79.0 × 2.74	98.4 × 2.74	117.8 × 2.74	156.6 × 2.74
Capacity [pas.]		385	585	785	985	1184	1584
Frequency [min]	0.5	46,200	70,200	94,200	118,200	142,080	190,080
	1	23,100	35,100	47,100	59,100	71,040	95,040
	2	11,550	17,550	23,550	29,550	35,520	47,520
	3	7700	11,700	15,700	19,700	23,680	31,680
	5	4620	7020	9420	11,820	14,208	19,008
	7.5	3080	4680	6280	7880	9472	12,672
	10	2310	3510	4710	5910	7104	9504
	12	1925	2925	3925	4925	5920	7920
	15	1540	2340	3140	3940	4736	6336
	20	1155	1755	2355	2955	3552	4752
	30	770	1170	1570	1970	2368	3168
	60	385	585	785	985	1184	1584

Source: own study.

). Metro routes are characterised by extremely high transport capacity. Due to traffic safety and operational constraints, the maximum value of 190,080 passengers/h/direction is technically and operationally impossible in a metro corridor. With an advanced traffic control system and efficient passenger exchange, operations with a maximum frequency of 1 min are technically possible, transporting 95,040 passengers/h/direction. The Warsaw Metro, operating at a maximum frequency of 2 min 20 s, enables transporting approximately 30,000 passengers/h/direction. Six-segment trains are operated in the system.

The study’s realistic value (95,040 passengers/h/direction) perfectly matches the upper limit from the literature (up to 100,000 passengers/h/direction). Warsaw’s current operational figure from documents (30,000 passengers/h/direction) is within the expected normal range for non-saturated metro lines, with an operation of 6-segment-car trains in frequency of 2:30 or 2:50 on the I and II metro lines. In night operation, metro service is provided every 15 min, meaning the capacity of 4736 passengers/h. The most used metro trains have between 4 and 6 segments and operate at a frequency between 2 and 10 min, so the standard capacity of this transport mode is between 4710 and 35,520 passengers/h/direction. If the frequency in the designing stage is expected to be lower than 15 min, different transport mode should be considered – a bus or a tram.

4.4. Urban Railway Transport Capacity Matrix

The last determined matrix was for urban railway transport capacity (see

Table 6. Urban (agglomeration) railway transport design capacity matrix [pas./h/direction].

		Urban Railway
Vehicle Class Vehicle Model		1 Seg Pesa	2 Seg Flirt	3 Seg Flirt	4 Seg Flirt	5 Seg Flirt	6 Seg Flirt	8 Seg Flirt	2 × 5 Seg Flirt
Dimensions [l × w]		28.1 × 2.82	45.7 × 2.82	63.2 × 2.82	80.7 × 2.82	98.2 × 2.82	106.6 × 2.82	150.2 × 2.82	196.4 × 2.82
Capacity [pas.]		162	268	406	542	690	725	928	1380
Frequency [min]	0.5	19,440	32,160	48,720	65,040	82,800	87,000	111,360	165,600
	1	9720	16,080	24,360	32,520	41,400	43,500	55,680	82,800
	2	4860	8040	12,180	16,260	20,700	21,750	27,840	41,400
	3	3240	5360	8120	10,840	13,800	14,500	18,560	27,600
	5	1944	3216	4872	6504	8280	8700	11,136	16,560
	7.5	1296	2144	3248	4336	5520	5800	7424	11,040
	10	972	1608	2436	3252	4140	4350	5568	8280
	12	810	1340	2030	2710	3450	3625	4640	6900
	15	648	1072	1624	2168	2760	2900	3712	5520
	20	486	804	1218	1626	2070	2175	2784	4140
	30	324	536	812	1084	1380	1450	1856	2760
	60	162	268	406	542	690	725	928	1380

Source: own study.

). Urban railway corridors are characterised by high transport capacity, primarily due to the long and spacious rolling stock that can be assigned to train operations. Considering platform layout and railway traffic safety, 0.5 and 1 min frequencies were deemed impossible to achieve. It was assumed that with an advanced traffic control system and efficient passenger exchange, operations with a maximum frequency of 2 min are possible, allowing transportation of 41,400 passengers/h/direction.

The study’s 41,400 passengers/h/direction fits the realistic operational range for urban railway corridors. It confirms that suburban/urban railways have a lower maximum capacity than metro lines but much higher than trams or buses. In standard operation, 4–10 segment trains are used as an urban railway transport, with a frequency of 2–10 min, which means the transport corridor capacity ranges from 3252 up to 41,400 passengers/h/direction. Railway transport provides the highest range of vehicle lengths that can be used (platforms for up to 200 m long vehicles or even longer, depending on the railway infrastructure manager’s standard). It is also common that every train on the railway corridor can have a diverse set and direction of travel (ca. 30–200 m long), so this mode of transport is highly customisable to the passenger demand, more than fixed-length metro sets in corridors.

5. Discussion

Specific vehicle models can vary with equipment and structure of the passenger compartment, regarding the type and number of driver’s cabin, engine and battery placement, ticket vending machines and other elements installed in the passenger compartment. To unify comparisons between transport modes, for research, the most commonly used types of vehicles were considered with a standard passenger compartment arrangement. Changes in the same vehicle type between operators are up to a few seats/standing places. The error connected with the calculations is assumed to be low, around 5%, greater for small vehicles such as a bus and smaller for high-capacity vehicles.

Comparison of the vehicles’ possible passenger density shows the transport modes in which passengers mostly stand and those with a better ratio of seating places, comparing the design capacity at E LOS (the basic capacity of PT systems). The passenger density in the vehicle is the biggest in metro system (between 3.50 and 3.69 people/m²), trams are second in that parameter (2.74–3.16 people/m²), then buses (2.54–2.82 people/m²), and the least people on the m² are in urban multiple train units (2.04–2.49 people/m²). That means the most comfortable for passengers are modern train units and the least are metro sets. The consequent data have also been provided for C and D LOS. Design capacity matrices have only been prepared for the maximum acceptable load (E LOS) that does not lead to the crush load conditions and unstable PT service.

In the zero-emission transport era, trolleybuses with battery packs did not receive much greater adoption than buses. Still, the highest issue is the excessive cost of trolleybus infrastructure and the intrusion of the wire traction network in the city landscape. Building expensive infrastructure is more reasonable for much longer vehicles (such as 24-m-long vehicles or trams/metros/urban railways). Those were the reasons behind the connection of both modes into one matrix. The CBA effects for electric buses are various, both positive and negative. Because of the battery packs, the smaller passenger compartment makes those vehicles less economically effective. The most significant economic advantages are the lack of exhaustion and smaller noise emissions. Other effects are highly dependent on the current price of fuel and energy.

Urban railways often share the same tracks with urban, regional, and long-distance trains. That situation usually ruins the operation in even intervals of urban railways. It is difficult to maintain even headway between various categories of trains. Only some highly advanced railway networks separate traffic on different tracks. Reaching the highest frequencies is connected with the operation of highly advanced traffic control systems, such as the European Train Control System (ETCS), at least at level 2 (1.5–2 min headway) [58].

One of the main parameters influencing the service frequency in the operation of PT is punctuality, which is also one of the most critical parameters of PT quality [59]. Building an urban PT network with high-capacity corridors means providing access-controlled and collision-free routes, which help to avoid congestion and sustain high punctuality. Because of separate tracks and access control, it is easier to give a higher punctuality rate in railway transport than in bus transportation. Furthermore, high frequency rate determines the decreasing punctuality rate of the service, so the highest frequency values are the most difficult to sustain. High volume corridors require a whole network of feeder connections, which will provide additional passengers at the PT hubs. An alternative option to regular feeder PT lines is demand responsive transport (DRT), which could give additional transfer passengers for built high-capacity PT corridors. Some research indicates that it could be a more punctual and flexible solution for suburban areas, increasing the overall performance of PT in urban areas [60]. However, it must be remembered that DRT is a solution for low-volume PT. It is serviced by little buses with a capacity of up to over a dozen passengers so that they will have minimal influence on PT’s overall network capacities.

6. Conclusions

The developed transport capacity matrices allow for comparisons between different conceptual and design solutions for servicing cities and metropolitan areas with various transport modes and vehicle classes. Incorporating the matrix into the conceptual and design work for new public transport corridors is recommended.

Rolling stock manufacturers apply different standards for the number of passengers per m² of floor space; the most significant disproportion refers to buses (less stringent standard) and trams (more stringent standard). The basis for determining vehicle capacity for trams and trolleybuses is a standard of one passenger per 0.2 m² of space. In contrast, capacity for buses, metro trains, and railway vehicles is based on the permissible total vehicle weight (resulting in between 0.1 and 0.15 m² of space per passenger). This issue should be regulated in the technical requirements for public transport vehicles. It is proposed to introduce a uniform standard of 0.2 m² of space per standing passenger across all vehicle types, which is also E LOS indicated in the literature.

The transition from HF to LF rolling stock (buses and trams) has reduced passenger capacity due to technical constraints of individual modes of transport. At the same time, trams used in most Polish cities (2.4 m wide) are narrower than buses (2.55 m wide) and have a higher proportion of standing space. This is determined by the tram track sections’ width and gauge. To increase tram transport capacity, consideration should be given to extending tram sets and widening cross-sections to accommodate wider vehicles, allowing for more seats or expanded standing space. If more seating were provided, such solutions would improve passenger comfort, particularly for longer tram journeys.

Another change in bus transport capacity was provided by a change in the bus’s energy source, transforming diesel and hybrid vehicles into fully electric or hydrogen-powered zero-emission buses. The construction of such a vehicle limits passenger space because of the batteries installed inside the passenger compartment and the vehicle’s total weight limits. The battery size varies depending on the energy located in the package. In trolleybuses, the battery packs are the lowest, starting from 30–40 kWh, and in electric buses, they could end up being 600 kWh for the biggest range. With the development of technology, the energy density of batteries is growing, so the size of battery packages is lowering, and with time, that factor will be less critical. That is the most significant change in the recent decade influencing the public transport capacity matrices. Other means of public transport (trams, trains and metros) have been mainly zero-emission for decades.

Metro and urban railway systems have the highest and comparable transport capacities, but the determining factor is the maximum frequency achieved within a given transport corridor. Given this and the excessive cost of constructing underground metro lines, it is recommended to expand the use of railways in urban and metropolitan transport by adapting existing corridors in cities. This would enable the creation of high-capacity corridors, which are notably lacking in urban public transport networks, especially during peak hours.

The study’s calculated capacity matrices values align closely with figures in the literature review for buses, trams, metro and urban railway corridors. Realistic operational capacities proposed in the study are consistent with real-world examples, confirming the accuracy and applicability of the developed methodology. Although theoretical maximum capacities are higher, they reflect ideal conditions and highlight potential improvements under optimised operations. The study provides a reliable and standardised framework for evaluating and comparing public transport corridor capacities.

If the metro corridor is planned for providing capacity of values in yellow (up to 5000 passengers/h/direction) or lower, the bus transport should be considered; and in green (up to 25,000 passengers/h/direction), the tram transport should be considered. Based on the data shown in the above tables, it can be concluded that the standard corridor capacity for bus transportation is up to 7800 passengers/h/direction, for trams up to 12,900 passengers/h/direction, metros 35,520 passengers/h/direction and urban trains 27,600 passengers/h/direction. The matrices divided PT modes into three subgroups: low-capacity buses, medium-capacity trams, high-capacity metros and urban railways.

The methodological approach adopted in this study is designed to be replicable across diverse urban contexts, provided that vehicles’ local operational and technological parameters are appropriately adapted. Publicly available operational data (such as General Transit Feed Specification GTFS [61]) and Geographic Information System (GIS) tools can be used to determine corridor capacity in the whole urban PT network. Combining it with scenario-based modelling (e.g., PTV Visum software for 4-staged macro-scale traffic simulation), the method systematically evaluates zero-emission transport capacity under varying urban densities, service patterns and fleet compositions. This methodological structure can be transferred to other cities or regions undergoing decarbonisation of their public transport systems, enabling comparative analysis and evidence-based planning. However, successful replication requires calibration to local factors, including modes of transportation, network topography, and regulatory and operational frameworks. Moreover, similar comparisons in tables can be performed for general road traffic, considering the number of passengers in a car and the number of road lanes.

The created matrix can help urban designers select an appropriate mode of transport for their projects regarding the expected volume of passengers at the corridor per rush hour in one direction. The selection is between the cheapest mode of transport buses with the lowest corridor passenger capacity, medium values for the trams and the highest capacity but also the highest investment and operational costs for metro or urban railway. The study’s results can contribute to sustainable mobility and urban planning actions and strategies by helping to select the optimal mode of transportation, according to input data for the selected PT corridor or network. The matrix can provide input data for CBA analysis of different scenarios of transport investment, which could lead to a comparison of net present value (NPV) and internal rate of return (IRR) indicators in economic analysis that is closer to a real-life situation.

The matrices can be further expanded to all LOS levels to show variation of capacities that can be provided during peak and off-peak periods for different directions and the passenger exchange rate within transport corridors. This would help determine the potential maximum number of passengers on existing transport corridors. Furthermore, PT corridor capacities could be compared with the capacity of roadways as part of calculating traffic distribution and effectiveness of transport corridors. Such analyses could be the subject of further research.