Different spatio-temporal dimensions of urban traffic congestion

Abstract

Urban traffic congestion is intractable. Though numerous studies have attempted to unravel this issue, traffic jams are still pervasive. To formulate effective remedies, it is important to unveil its geographical characteristics. Less scholarly attention, however, has been paid to it. From the geographical perspective, this thesis aims to investigate urban traffic congestion from different spatio-temporal dimensions. First, after collecting 40,324 pieces of traffic congestion-related news in 12 cities (i.e. Auckland, Beijing, Bengaluru, Hong Kong, Jakarta, Kuala Lumpur, London, Los Angeles, Manila, Singapore, Sydney, and Toronto) from 2009 to 2018, this thesis conducted the thematic analysis to reveal the underlying themes vis-à-vis sustainable transport and congested-mitigation measures. And a sentiment analysis is performed to examine the level of frustration expressed. Results pinpointed that as concerns over the environmental impacts were increasingly discussed, traffic congestion is no longer seen as a major economic issue. Also, terms related to promoting public and active transport were the most popular. Additionally, there is a positive association between the traffic congestion level and the congestion frustration level expressed in local news. As for the delineation of congestion areas in cities, this thesis introduced a spatial approach to identify congested areas within cities. Results obtained are validated against the empirical traffic speed data in four Asian cities (i.e. Bangkok, Hong Kong, Kuala Lumpur, and Singapore) from 2018 to 2020. Compared with the conventional method using job density to identify congested areas, results corroborated that the proposed spatial approach is both efficient and effective. Insights for the delineation of the congestion charging boundary are also provided. Another congestion alleviation antidote, working-from-home (WFH) arrangement, has also been investigated. Focusing on human activities, this thesis used a set of longitudinal GPS tracking data in Switzerland to analyse changes in trip characteristics (travel distance, travel time), travel behaviours (travel frequency, peak hour departure, trip destination, travel mode), and activities (trip pattern diversity, trip purpose, time spent at home). Two groups of participants (WFH and Non-WFH) are identified and compared through three periods (pre-COVID, during lockdown, and post lockdown). Results suggested that promoting WFH may not only be beneficial to teleworkers but also to the wider community through mitigating negative transport externalities. To further provide empirical evidence on the impacts of WFH arrangement on road traffic, this thesis explored changes in road traffic at peak hours throughout

different waves of pandemic in Hong Kong from February 2020 to July 2021. Results demonstrated that peak-hour congestion has been alleviated under WFH arrangement, especially at the morning peak. Spatially, significant alleviations of traffic conditions were detected not only in the CBD but also in some new towns. The spatio-temporal variations of road traffic changes have significant impacts for scholars and urban planners in creating more sustainable cities. Overall, findings highlighted the significance of the geographical perspective in traffic congestion research. Results also recognised that there is no panacea to alleviate traffic congestion. It is anticipated that findings of this thesis can augment the understanding of traffic congestion, therefore furnishing congestion-related policy implications.