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Real-time emissions of gaseous pollutants from vehicles under heterogeneous traffic conditions

Goyal Yuvraj, Meena Sanu, Singh Suresh Kumar, Kulshrestha Mukul

Zeszyty Naukowe. Transport / Politechnika Śląska

2023

z. 118

55--75

Air quality problems in cities are often a cause for worry. The air quality index is increasing daily, leading to an increase in cancer and many respiratory problems. Road transport in an urban area is a significant cause of air pollution. The vehicles must meet Indian emission regulations for which the emissions are measured using legally mandated standard driving cycles that did not accurately reflect real-world driving emissions because of varying traffic conditions, meteorological conditions, driving behaviour, vehicle power, performance, etc. This study focuses on real-time emissions of gaseous pollutants hydrocarbon (HC), carbon dioxide (CO2), carbon monoxide (CO), and nitric oxide (NO) from vehicle exhaust pipes under heterogeneous traffic conditions. The emissions were measured using a Portable Emission Measurement System (PEMS). The PEMS used was an AVL MDS 450 analyser mounted on the vehicle, and onroad emissions were captured. The test sample consists of four passenger vehicles with varying engine sizes, manufacturers, and fuel. The test route comprises city and highway areas, and it was discovered that the emissions were reduced by 40 to 70% on highways compared to the city. In petrol BSIV and BSVI engines, the emission was reduced to 41.73% for CO, 46.90% for HC, and 64% for NO in the city area. Speed and emissions scatter graphs were plotted for the vehicles, and it was found that in the city area, the optimum speed for less emission is between 30-40 km/h, and on highways, the optimum speed is 80-90 km/h. The emissions were also sensitive to the rate and frequency of acceleration and decelerations. This type of study is very limited in India, and more such studies are required for the assessment of air quality in metropolitan areas and successful traffic management strategies, as well as for determining instantaneous projections of pollutant emissions.

Development of the travel satisfaction scale (TSS) for the assessment of commuters’ satisfaction in public transport: evidence from Delhi metro (India)

Solanki Sachin, Meena Sanu, Kumar Umesh

Zeszyty Naukowe. Transport / Politechnika Śląska

2022

z. 117

233--245

The Travel Satisfaction Scale (TSS) was created to gauge public opinion on Delhi Metro travel. It has two affective dimensions and one cognitive dimension. This study leverages data from the Delhi Metro commuter trips to undertake new tests because there has been little research on its reliability and structure in the past. Differences in the TSS's reliability and structure – notably for the Delhi Metro and the demographics of the region – are also considered. Finally, the outcomes of this study imply that a single dimension of the affective dimension, rather than the two sub-dimensions, provides a better fit for the Delhi Metro, as well as other public transportation infrastructures in developing countries like India. Individual objects do not load on the two emotional dimensions as intended in a three-dimensional structure, which is more suited for public transportation. Two of the scale's elements – enthusiastic/bored and relaxed/hurried – were associated with the other items in a previous study differing from ours. Researchers should adapt the structure of the TSS in the future by adding or replacing some items with alternate options, which will make it easier to collect data and reduce the burden on the respondent, as well as increase the reliability of the data while maintaining the TSS's consistency and balance.