# Quality of Service Criteria in Integrated Passenger Transport Systems: An Overview
## 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 One major challenge is the issue of unreliable service and frequent delays caused by traffic congestion, outdated infrastructure and operational inefficiencies, which erode trust among passengers.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 Outdated infrastructure remains a critical obstacle, with poorly maintained vehicles, transit lines and facilities resulting in breakdowns, safety risks and reduced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.