Analysis of the temporal structure of vehicle flow in cities and a potential application to noise pollution

Abstract

This paper first proposes a methodological approach for analysing the urban road traffic flow. It hypothesizes that the temporal structure of the flow through the streets of a city is sufficiently uniform to define a single variable to describe the temporal variability of the flow, in one-hour intervals, throughout the city. Data from 54 road traffic flow monitoring stations were collected on an hourly basis during 2019 in Madrid, Spain. Then, the mean hourly flow ratio (MHFR) was defined and considered to test the hypothesis. The analyses carried out allow to conclude that the variable defined is adequate to describe the hourly time structure of the flow of road traffic over the course of a year on the streets of the city studied. This result opens the possibility that the temporal variability of environmental variables related to road traffic flow could be studied by using a single independent variable, with an accuracy of one hour, and valid throughout the whole city. Noise pollution is a serious environmental problem that, in our cities, is closely related to vehicle traffic. Consequently, as an example of applicability of MHFR, a study of the relation between hourly equivalent sound level (LAeq,1h) and MHFR was carried out. To do this, data recorded hourly throughout 2019 by 31 noise level measurement stations in Madrid were considered. As a result of this study, highly statistically significant positive correlations were found between the MHFR variable and the data corresponding to each of the noise monitoring stations. These findings suggest that the MHFR variable can be used for appropriate decision making on urban road traffic management, meaning that it can contribute to reducing the impact on the population of noise pollution and other pollutants associated with the hourly variation of traffic flow.