# Impact of Environmental Factors on Passenger Ride Comfort
## 8 Conclusions  
This article analyses the influence of environmental factors on passenger comfort in different modes of transport, including a mid-range passenger car and two types of metro trains. The original method of the comfort assessment, described in this paper, takes into account four main types of ride comfort: vibrational, acoustic, thermal, and visual. The aim of this study was to identify the environmental factors influencing the overall level of comfort. The method is based on a synthetic index of overall comfort, defined as the minimum value among the ratings of the above-mentioned different types of comfort. Each factor was assessed on a five-point scale. In order to be able to compare modes of transport with each other, the comfort levels of the individual comfort factors are based on the recommendations of international standards and the recommendations of relevant institutions. This study demonstrated that the highest level of comfort was achieved by the new metro trains in terms of visual comfort due to optimal lighting. In contrast, the lowest level of comfort was recorded for acoustic comfort, particularly in older trains and in the passenger car on the local road, where higher noise levels significantly reduce the level of comfort. The overall comfort index is limited by the lowest score among different types of comfort, suggesting that improved acoustic conditions could significantly affect passengers' perception of comfort. In particular, better insulation, modernised soundproofing technologies, and noise reduction measures in both vehicles and infrastructure would contribute to significant improvements in acoustic comfort. The application of the proposed method can contribute to the identification of areas for improvement in passenger transport for both the means of transport and the transport infrastructure. In particular, the present findings confirm that improving road surfaces, upgrading older trains, or even replacing the rolling stock can effectively improve ride comfort. Moreover, investing in higher-quality road surfaces and more advanced suspension systems in older vehicles could further reduce vibrations and enhance overall comfort. To address the identified issues of acoustic comfort in the passenger car, it is also worth considering introducing road maintenance programs aimed at resurfacing local roads and using noise-reducing asphalt, especially in high-traffic areas. For metro trains, retrofitting older trainsets with advanced insulation materials can be considered. Another solution is to install noise-absorbing barriers along metro lines or deploy real-time noise-monitoring systems to proactively address high-noise areas and improve maintenance schedules. Similar measures can be implemented to improve vibrational comfort. As for the thermal comfort in metro trains, it might be beneficial, especially in the context of the older rolling stock, to retrofit them with modern, energy-efficient HVAC systems that can improve thermal regulation. Moreover, enhancing thermal insulation can help maintain stable internal temperatures, reducing the load on HVAC systems and ensuring uniform comfort throughout the train. In the passenger car, the solution may be to improve existing cooling systems to handle higher temperatures effectively. This includes routine maintenance, refrigerant replacement, and upgrading to high-performance components. In addition, the awareness of the driver and passenger plays an important role. It is essential that users be aware of best practices for operating air-conditioning systems in extreme weather conditions, such as pre-cooling the car or using sun visors to reduce internal heat build-up. In the context of visual comfort, several improvement measures can be proposed. One of them is the replacement of ageing luminaires with energy-efficient LED systems, which can enhance brightness levels while reducing maintenance and operational costs.