Quality of Service Criteria in Integrated Passenger Transport Systems: An Overview

Abstract

Urban mobility (UM) refers to the movement of people and goods within urban areas. It is a multidimensional and dynamic aspect of urban life. Everyday mobility is constantly increasing. Therefore, encouraging a modal shift from private vehicles to more sustainable modes such as public passenger transport (PPT) often motivates the implementation of measures that improve service quality. Implementing improvements in public transport service quality is often expected to positively affect the demand for PPT. Therefore, quality of service (QoS) represents the basic criteria for the provided service. The European Standard EN 13816:2002 states the requirement to define, set a goal and measure the quality of service in PPT. It also provides guidelines for selecting appropriate measurement methods for determining the quality of service. Integrated passenger transport systems (IPTSs), because of their complexity and specificity (unified fare system, integrated and harmonised timetable, unified ticketing system and information system), should have different criteria levels. The current standard does not define specific criteria for IPTSs. Improving QoS criteria in IPTSs is essential for enhancing user satisfaction, making them more attractive, efficient and sustainable. This paper should determine basic QoS criteria for IPTSs.

1. Introduction

According to projections, 68% of the world’s population will live in urban areas, placing a significant burden on environmental management and existing infrastructure [1]. Creating sustainable and efficient urban mobility solutions is crucial for addressing the challenges of modern cities and ensuring a high quality of life for their residents. Nowadays, transport development is directly connected to the economic and social development of a given city or region. Transport has a strong influence on spatial structure at the local, regional and global levels [2].

UM encompasses the movement of people and goods within urban areas. It incorporates various transport modes, including walking, cycling and public and private transport, as well as shared mobility services like ridesharing and bike-sharing. It has become an increasingly important issue in recent years, as cities have faced growing traffic congestion, air pollution and other transport-related challenges [3]. Public transport services are systems designed for public use, playing a crucial role in UM. The advantages of public transport systems are numerous; they help ease traffic congestion, reduce air pollution, support sustainable mobility and enhance access to employment, education and healthcare services.

PPT can be defined as transport available for public use, a transport system (of buses, trains, etc.) that runs on fixed routes at set times [4]. PPT is commonly used by people commuting or travelling within a city or region. It can be used by anyone possessing a valid ticket or pass. One of the concepts of PPT organisation and management is the IPTS. It refers to a coordinated network of public transport services that enable passengers to travel between origin and destination points using various modes of transport. It is characterised by the integration of different modes of transport into a unified fare system, a unified integrated and harmonised timetable, a unified ticketing system and an information system [5]. It is stated that the increasing number of passengers in urban areas has encouraged new travel options (in addition to traditional ones), with multimodal travel being a promising option [6].

Presently, many case studies and research papers deal with the evaluation of PPT user satisfaction, considering EN 13816:2002 standard. Studies are entirely focused on analysing one mode of PPT. A notable research gap exists in the assessment of QoS within IPTS. This deficiency includes aspects such as the definition of QoS criteria levels and the development of approaches assessing service quality for various transport modes.

2. Urban Mobility

The global trend of urbanisation, coupled with economic growth, has led to increased transport demands on a daily basis. Transport demand is a key factor in developing transport services for specific areas or regions. Demand for transport can be characterised as a variable that expresses the demand for transport between locations [7].

Over recent decades, car ownership and the use of individual transport have expanded in many urban areas. This growth in individual transport contributes to heightened transport demand, resulting in escalating external costs for communities. External costs are generated by transport users and not paid by them but by society, such as congestion, air pollution, climate change, accidents and noise but also up- and downstream processes, costs to nature and the landscape or additional costs in urban areas [8]. Urban traffic congestion occurs when the volume of vehicles on the roads surpasses the infrastructure’s capacity, causing delays and increased fuel consumption and air pollution, particularly during peak hours.

The concept of sustainable UM has gained widespread recognition in many cities worldwide. It has brought a new understanding of organising UM around the objectives of wider accessibility, reduced car dependence, saving energy and reduced carbon emissions, which increases the liveability of the cities [9].

The modal shift in UM involves promoting the use of various transport alternatives, thereby reducing the dependence on individual transport in urban areas. The modal split represents the ratio of different transport modes in the total journey from the origin to the destination point [10,11]. A coordinated package of mutually reinforcing transport and land-use policies and measures is the key to a successful modal shift. Measures to encourage a modal shift to public transport can be separated into two main categories [9]:

• “Pull” measures—persuade the user to use public transport;
• “Push” measures—dissuade the user from using individual transport.

Over the past 25 years, Vienna succeeded in reducing the car share of trips from 40% to 27%, Munich from 40% to 33%, Berlin from 35% to 30%, Zurich from 39% to 30% and Hamburg from 48% to 42% [12]. The five cities have established a unified framework of complementary transport and land-use policies that, when considered together, have led to a decline in the speed, convenience and affordability of individual transport. At the same time, these policies have endorsed safety, the convenience and practicality of walking, cycling and public transport.

Modal shift is an important element of sustainable mobility planning, as it helps reduce transport’s environmental impact and improve the quality of life for people living in urban areas. PPT systems worldwide are undergoing significant transformations driven by technological advancements, environmental concerns and changing urban mobility policies.

3. Integrated Passenger Transport Systems

Public transport systems are set up to provide an attractive chain of services in the “door to door” relationship, integrating a combination of different means of public transport, public and individual transport and transport policy regarding spatial planning or investment in infrastructure [13]. Public transport systems are traditionally operated in large cities and densely populated areas but are also very feasible in rural areas [14].

An IPTS is conceptualised as an organisational mechanism that integrates various elements of the public transport framework, such as network infrastructure, fare systems, ticketing, information services and marketing strategies. This system is supported by a consortium of transport providers who operate different modes of transport and engage in closer, more efficient interactions. The outcome of this collaborative effort is a marked improvement in both travel conditions and the quality of transport services. The IPTS represents a holistic public transport solution designed to offer passengers, viewed as customers in an economic context, effective and affordable travel alternatives.

It aims to provide a comprehensive and integrated approach to passenger transport that considers various modes of transport and integrates them into a unified system. This includes providing frequent and reliable services, reducing total travel times, improving connectivity and passengers’ transfers between different modes of transport. This process can be quite complex, as it requires the synchronisation of different transport service providers and substantial investment in infrastructure and technology.

By implementing IPTS, the benefits arise for the following parties [14]:

• Customers of the public passenger transport service;
• Local government;
• Transport provider;
• The economy.

Such a system benefits from the advantages of each transport mode and simultaneously turns the downsides of every mode into the advantages of the other methods of transport [15]. It is essential that every mode of public transport collaborate effectively with other transport modalities, with a primary focus on prioritising the needs of customers throughout the entire system.

The integration of urban transport may take place at different levels [16]:

• Infrastructural;
• Organisational;
• Economic and financial;
• Informational;
• Spatial.

Based on the results of eleven case studies, results show that the existence of a business rationale in the integration of transport services could be exploited through the implementation of an adequate business model and that IPTS implementation at the regional level can achieve satisfaction among 81% of users [17].

Integrovaný dopravní systém Jihomoravského kraje (IDS JMK) operates within the entire South Moravian region (Czech Republic) and parts of the Vysočina, Zlín, Pardubice and Olomouc regions bordering the South Moravian region, as well as in parts of Slovakia and Austria. The IDS JMK integration area is divided into 161 fare zones in which 25 operators operate: Brno city transport companies, 5 train carriers and 19 regional bus lines. The total number of routes is 322, of which 71 lines (bus, tram and trolleybus) are in the City of Brno transport system; 33 city transport lines are in other cities (Břeclav, Hodonín, Vyškov, Kyjov, Blansko, Adamov, Bystřice nad Pernštejnem, and Znojmo). There are 24 lines of rail transport, while there are 194 lines of regional bus transport [18]. The main advantage of IDS JMK is unified fares for the entire region. The area of IDS JMK is divided into the so-called fare zones. The core of the fare system are zones 100 and 101, which cover the territory of the City of Brno. Adjacent to them are other areas, typically comprising multiple municipalities or a major city. This approach significantly enhances the clarity and travel speed for passengers, allowing them to easily determine the cost of any journey within the IDS JMK region based on the number of zones they traverse. Following the launch of IDS JMK, there has been an increase in the number of services available in the region. Passengers now have access to more destinations than previously due to improved service frequency and well-planned transfers. Timetables for IDS JMK were created from scratch, featuring a consistent design that enhances readability.

Numerous cities and regions worldwide have successfully implemented IPTSs to enhance transport alternatives for both residents and tourists.

4. Public Passenger Transport Service Quality

The term “quality” has a relative meaning. It is used in numerous ways and there is no clear definition. According to the International Organization for Standardization, “Quality is the degree to which a set of inherent characteristics meets the requirements” [19]. For consumers, the association lies primarily with the utility or the price of the product. On the other hand, providers relate it to the design and manufacturing elements involved in production. The quality of a product or service is determined by the relationship between the requirements and needs of the customer and their realisation by the provider [20].

“Quality of transport” refers to the overall standard of transport services, whether they are public or private, aimed at the movement of individuals, goods or services. This concept includes a range of elements that influence the efficiency, safety, reliability and convenience of transport. Public transport services are usually operated by local government authorities or transport providers (operators) and are designed to provide passengers (customers) with affordable, convenient and reliable transport options. However, an increase in supply (qualitatively or quantitatively) will not automatically lead to a corresponding increase in demand and satisfaction [21]. Upgrading service quality is the key element in increasing the number of customers in PPT [22].

The quality of public transport can be analysed from two different points of view: (1) the service provider’s and (2) the passengers’ (in a broader sense: users’) points of view [23]. It can vary significantly from one city or area to another and even within the region. Different modes of public transport may exhibit varying levels of quality. It is important to identify which are the attributes perceived as relevant by the customers.

One case study [23] measured service quality variations in a set of integrated policies implemented in the Campania region (Italy) going under the name of the Regional Metro System (RMS). One of the conclusions is that the quality of public transport depends on several service criteria, some of which are quantitative. (e.g., average travel time and its reliability, transit waiting time, monetary costs), while others are qualitative, whose effects on user behaviour are more difficult to assess (e.g., riding comfort, information, personal security).

Improving the quality of public transport often requires ongoing investment, strategic planning and collaboration between governments, transport authorities and public transport operators. Gathering feedback from passengers and conducting regular assessments can help identify areas for improvement and guide efforts to enhance the system’s quality. Nowadays, quality has a growing importance in the field of transport [24].

4.1. Quality of Service in Public Passenger Transport

Quality of service (QoS), in the context of public transport, refers to the level of service provided to customers. It focuses on meeting customers’ needs and expectations to encourage greater use of public transport. Improving QoS is essential for attracting new customers, reducing traffic congestion and promoting sustainable mobility.

QoS serves as a framework for describing or measuring the overall performance of transport services, particularly from users’ perspectives. To ensure that PPT remains a viable alternative to the increasingly prevalent individual transport, particularly in road networks, achieving and maintaining high-quality standards is essential. QoS plays a crucial role in influencing transport demand.

EN 13816 is a European standard for public transport services. The document outlines necessary standards for QoS that PPT providers are required to offer to their customers. It establishes a comprehensive set of indicators and criteria for evaluating QoS, which transport providers can apply to evaluate their performance and identify areas that require enhancement. The primary objective of the standard is to encourage a quality-oriented approach to PPT service performance, prioritising the needs and expectations of the customers. Customers’ views of PPT service quality are concerned with the following [24]:

• Sought service quality—level of quality required by the customer;
• Targeted service quality—presents a level of quality which the provider aims to provide for the customers;
• Delivered service quality—on a day-to-day basis, achieved the level of quality measured from the customer viewpoint;
• Perceived service quality—customer perception of the delivered quality.

The distinction between “sought quality” and “targeted quality” is the degree to which the service provider can focus its efforts on the areas that are important to the customers of the service. The difference between “targeted quality” and “delivered quality” is a measure of the service provider’s efficiency in achieving their targets. Perceived quality sometimes has little to do with the delivered quality. Perceived quality can be measured through surveys.

This European standard targets and measures service quality in PPT and provides guidelines for the selection of related measurement methods. The overall quality of PPT contains many criteria. The criteria represent the customers’ view of the service provided, and in Standard EN 13816, they have been divided into 8 categories [24]:

• Availability;
• Accessibility;
• Information;
• Time;
• Customer care;
• Comfort;
• Security;
• Environmental impact.

Availability is a critical QoS criterion for PPT, as it directly impacts the suitability and dependability of the service to potential customers. This category includes the extent to which the transport network covers the region or a specific area, frequency of service, need for transfers and hours of operation. It is defined by the need for change between PPT modes and ratio of passengers actually carried as against the total capacity of a vehicle.

Accessibility refers to the ease with which passengers can use the service, including internal movement and transfer to other PPT modes. It implies the possibility of buying a ticket on/off the PPT network and its validation. Also, an external connection to all groups of potential users must be ensured.

Information covers the area about quality and availability of information provided to customers. Systematic provision of knowledge about a PPT system is necessary to assist in the planning and execution of journeys. The category includes information about route, time, fare and available alternatives in case of emergency circumstances.

Category time is described by the length of trip time, which consists of trip planning, access/egress points on the network and of the in-vehicle travel time. Adherence to schedule is outlined by accuracy and regularity of the timetable.

Customer care elements are introduced to affect the closest practicable match between the standard service and the requirements of any individual customer. Also, it refers to the quality of interaction between the transport provider and the passengers, including the behaviour, helpfulness and skills of staff, handling of complaints, overall customer service and ticketing options.

Comfort includes criteria introduced for the purpose of making PPT journeys relaxing and pleasurable. The category represents ease of passenger movement and physical comfort in the vehicles and waiting areas, such as seating, cleanliness, temperature control and noise levels.

Security covers the safety and security of PPT users, including measures to prevent accidents, crime and harassment and the presence of security personnel and surveillance systems. It also includes emergency management, facilities and plans. It expresses a sense of personal protection experienced by customers.

Environmental impact is described as an impact on the environment resulting from the provision of PPT services. It is defined by the impact on pollution, natural resources and infrastructure, as well as emissions, noise, pollution, vibration and energy efficiency.

There are few studies on the quality of PPT, especially in the cases of specific transport modes [25,26]. Most studies approach QoS of transport modes in certain geographic areas [27] or specific groups of users [28].

Innovative approaches in PPT can significantly enhance QoS by addressing common issues such as inefficiency, overcrowding, delays and passenger dissatisfaction. The shift from fossil fuel-powered vehicles to electric buses, trams and trains is gaining momentum globally. Studies highlight the environmental benefits of electrification, including reduced greenhouse gas emissions and improved air quality [29]. However, challenges such as high upfront costs, battery technology limitations and charging infrastructure requirements remain significant barriers [30].

PPT are undergoing significant transformations driven by technological advancements. These changes aim to enhance efficiency, sustainability, accessibility and user experience. Intelligent transport systems (ITS) leverage information and communication technologies to improve the management and operation of public transport networks by real-time monitoring of vehicle locations, passenger loads and traffic conditions allowing dynamic scheduling and route optimisation [31]. Contactless payment systems and mobile ticketing apps have streamlined fare collection, reducing boarding times and improving user convenience [32].

4.2. Customer Perceptions of the Quality of Service Criteria in Public Passenger Transport

Customers generally have a tendency to compare the service they “experience” with the service they “expect”. Customers criteria of the QoS in public transport plays a crucial role in determining public transport systems’ overall satisfaction and usage patterns. These criteria can significantly impact trips, revenue and the reputation of transport providers.

Analysing studies of real-world PPT improvements generally reveal that regardless of the criteria targeted, PPT improvements tend to achieve some level of increase in customer satisfaction or modal shift from individual transport. It is concluded that PPT services have the potential to attract individual transport users by improving the QoS.

Findings [33] show that PPT customer satisfaction is influenced by the following:

• Perceived value;
• Perceived usefulness;
• Image (customers opinion);
• Perceived ease of use (use does not affect PPT satisfaction).

A case study [34] analysed five bus terminals in Italy. The results show that perceived quality varies within the characteristics of the entire trip. Even if a passenger passes through a high-quality terminal, the overall quality of the trip is perceived as “low” for the 46% of the customers that take a “long trip” (travel time of “low quality” and greater than 2 h) or use more than one transport mode (if at least one is of “low quality”, e.g., subway and bus; bus and train). The opposite occurs for the “short trips”.

Article [35] raises four services of quality perceived attributes:

• Comfort;
• Safety;
• Convenience;
• Aesthetics.

The QoS measurement scale identifies three different quality criteria [36]:

• Service planning and reliability;
• Comfort and ancillary factors;
• Network design.

The paper [37] indicates that six criteria cover QoS in PPT:

• Safety;
• Service provision;
• Unwanted arousal;
• Cost;
• Access;
• Self-image.

Moreover, the QoS in PPT services is not evaluated in isolation, with users also weighing up the quality of individual transport and other transport modes in their quality evaluations. In one study [38], users’ service satisfaction was found to be critical in their evaluation of public transport services and resulted in loyalty to a certain transport mode. This study investigated public transit passengers’ behaviour by constructing a comprehensive model considering public transit involvement, service quality, perceived value, satisfaction and behavioural intentions.

Monitoring and addressing these criteria can help improve customers’ perceptions of the QoS in public transport. Regular feedback collection, performance tracking and continuous improvement initiatives can play a significant role in enhancing the overall experience for passengers. The QoS criteria define a level of satisfaction and reflect distinctions between the groups of users. The most satisfied group of users are retired people, while most of the objections to PPT are made by students [39].

5. Defining Quality of Service Criteria in Integrated Passenger Transport Systems

Quality has a fundamental influence on passenger transport services. The main objective of transport is to satisfy customers. Assessing the quality of public transport services involves evaluating various aspects to ensure they meet customers’ needs efficiently, safely and comfortably. From the passenger’s point of view, it is necessary to assess the availability of travelling opportunities between selected points on the network.

An IPTS is a more comprehensive approach to passenger transport that involves various transport modes and aims to provide customers with seamless, coordinated and convenient travel options [40]. Due to its main characteristics (unified fare system, integrated and harmonised timetable, unified ticketing system and information system) and various transport modes, an IPTS should primarily specify QoS based on the transport network instead of analysing PPT modes separately.

Because of its complexity, an IPTS should value and prioritise QoS criteria differently than PPT. The 8 categories of criteria, which represent customers’ views of provided service for PPT and an IPTS, are contained in

Table 1. Quality of service in public passenger transport services [41].

Category	PPT/IPTS Offer	PPT Service	IPTS Service
1.	general	availability	network
2.	general	accessibility	internal interface
3.	detailed	information	integrated travel information
4.	detailed	time	total travel time
5.	detailed	customer care	customer care
6.	detailed	comfort	comfort
7.	detailed	security	security
8.	environmental	environmental impact	environmental impact

.

By realising the advantages of a well-established IPTS, the two categories that describe the transfer offer more generally should be based on IPTS instead of a basic PPT system. The travel offer from origin to destination is, in principle, affected by travel information, travel time, number of transfers (changing the transport means) and number of travel opportunities [42].

Information is one of the detailed category contributing to public transport QoS. Many trips require various transport modes to accomplish the journey destination, so information must cover the entire “door to door” journey. This perceptual dimension indicates that the customer must adapt to the daily changing situations during his journey. Technological possibilities allow passengers to adapt to different travel scenarios [43]. Due to the concept of the IPTS organisation, every transport mode should provide travel information for users. Onwards, integration of travel information must provide travel information in the whole network in order to simplify transfers to other PPT modes. Thus, integrated travel information should be a detailed category of the QoS in the IPTS service.

An IPTS network consists of numerous transport providers, and the journeys may involve a transfer between transport modes. The customer experience of the total travel time is based on the overall journey, including transfers between PPT modes. In the end, the total travel time of the entire journey is relevant for the customer. For a journey with multiple transport modes, the total travel time includes the waiting time at the origin stop, the first in-vehicle time, transfer (walking) times between modes, waiting time at the next stop and the next in-vehicle time of the journey [44]. As a result, total travel time in IPTS represents a more complex and detailed category of QoS.

6. Conclusions

Public transport systems are subject to the influence of the dynamics of traffic flow, provision of transport services and passenger demand. Generally, it can be said that the most important thing is to provide enough connections and minimise the travel time for providing public transport that is competitive with individual transport. Nonetheless, improvements to the public transport system will lead to solving problems such as traffic congestion, accidents, traffic noise, air pollution and fuel consumption.

Delivering quality service in public transport is a complex task due to various challenges that hinder efficiency, reliability and user satisfaction. One major challenge is the issue of unreliable service and frequent delays caused by traffic congestion, outdated infrastructure and operational inefficiencies, which erode trust among passengers. Overcrowding is another concern, particularly during peak hours, as growing urban populations strain the limited capacity of public transport systems, leading to discomfort and inefficiency. Outdated infrastructure remains a critical obstacle, with poorly maintained vehicles, transit lines and facilities resulting in breakdowns, safety risks and reduced service quality. Additionally, inadequate funding often restricts the ability of transport operators to invest in modern infrastructure, advanced technologies, or expanded services. Environmental concerns also persist as many systems still rely on fuel-powered vehicles that contribute to harmful emissions, negatively impacting both public health and the environment.

Governments, transport authorities and public transport operators work together to improve the QoS in public transport systems. Regular feedback from passengers and continuous efforts to address their needs and preferences contribute to enhancing the overall quality and attractiveness of public transport. Specific criteria that contribute to QoS can differ between two types of public transport systems.

Standard EN 13816 is significant primarily because it offers service providers a proposal for defining QoS in PPT in one place, a proposal for evaluation criteria for service quality in PPT, a proposal for evaluating user satisfaction with PPT service and a proposal for quality management in PPT. Ultimately, QoS criteria do not have the same value to all public transport customers or transport providers.

The main objective of IPTS is to provide a comprehensive and integrated approach to passenger transport that considers various modes of transport and integrates them into a unified system. IPTS can offer more flexibility and convenience for passengers, who can choose from and transfer between various transport modes. Considering the above, IPTS is more complex than PPT. Network and transfers (to other PPT modes) should be basic categories that generally describe IPTSs. Because of their complexity and specificity, IPTSs should have detailed categories for integrated travel information and travel time for an entire journey.

Future research on the QoS for IPTS would involve assessing various aspects of the system’s performance to ensure a positive and efficient experience for passengers. Due to the need for integration, harmonisation and unification of different modes of transport, there is a need for more detailed QoS criteria for evaluating the quality of passenger transport services. Assessing QoS in such systems would involve evaluating various criteria that contribute to both passenger satisfaction and system performance.

To conduct comprehensive research on the QoS of IPTSs may require a combination of methods, including data analysis, passenger surveys, interviews with stakeholders, field observations and comparisons with similar systems in other regions. Research findings can provide valuable insights for policymakers, transport authorities and urban planners to enhance the efficiency and effectiveness of the integrated transport system.

Knowledge about what customers or potential users value in public transport systems, both PPT and IPTS, means policies can be designed to create an environment that would encourage them to use public transport. Identifying critical criteria for actual and potential customers serves as essential information for PPT providers. This insight allows them to implement customer satisfaction surveys designed to enhance the QoS. By ensuring high-quality public transport services, providers can not only retain their current customers but also attract new ones.