Preliminary assessment of vibration impacts generated by the public transport systems on pregnant women based on subjective reactions.

Abstract

Research efforts summarised in this study were a part of preliminary investigation to evaluate the impact of pregnant women's exposure to vibrations generated by public transport system when using. The assessment of the problem and discomfort for pregnant women, caused by the public transportation is based on a questionnaire including questions relating to the women's subjective feelings on well-being or discomfort when exposed to vibration during the ride in passenger cars or when using means of public transport. In the second stage of investigation, vibrations transmitted onto a sitting person during the tram or car ride were measured. The survey shows that when travelling on a tram the women complained mostly of digestive or neurological disorders, during the car ride they suffered most acutely from digestive disorders, sensed enhanced foetus movements and reported problems with the osteoarticular system. Amplitude-frequency characteristics of the investigated vehicle types reveal that vibration amplitudes registered during the ride in a motor vehicle are higher than on tram (in the analysed frequency range). Furthermore, vibration accelerations in the z-axis direction registered during the tram ride exceed the vibration discomfort threshold, particularly for the 1/3 octave bands 5 and 6.3 Hz. These are frequency ranges corresponding to resonance frequencies of vital organs in the abdominal cavity (4.5-10 Hz). Correlating these results with frequencies reported in literature associated with subjective human responses to vibration, shows that pregnant women using public transport are likely to suffer from a variety of ailments caused by vibrations generated during the ride.