9 to 5 or a new‐normal? Cluster analysis of pre and post pandemic vehicle and cycle diurnal flow profiles

Commuting traffic associated with the “9 to 5” workday shaped the morning and evening peaks across the world. The COVID‐19 pandemic led to unprecedented changes in travel behaviour such as an increase in cyclists and telecommuting, where employees worked from home during lockdown periods. Transport modellers, planners and policy makers need to know whether the 9 to 5 has returned, or we have entered a “New‐normal” of more flexible working arrangements and increased cycling, key for delivering sustainability targets. In this research, the unsupervised machine learning technique k‐means clustering investigates temporal patterns across the day and week, comparing the pre‐ and post‐pandemic era across both motorised vehicles and bicycles. Results show that the total daily traffic flow has returned to pre‐pandemic volumes, but more spread across the day. Mondays and Fridays have less‐pronounced peaks compared to pre‐pandemic, having implications for air quality modelling and assessment, traffic management and transport planning. Meanwhile, cycling has increased in volume and the time‐of‐day people are travelling has changed. Policy makers need to consider whether the additional capacity on the road, brought about by reduced peak traffic, could be reallocated to make roads safer for and reduce delay to cyclists, contributing towards net zero goals. The research presented in this paper identifies changes in both flow volumes and their temporal patterns across the day and week from the pre‐pandemic to post‐pandemic era across both motorised vehicles and cycling. This was achieved by using the unsupervised learning technique k‐means clustering on the diurnal flow profiles. Whilst vehicle traffic has returned to pre‐pandemic volumes, this study found that it is more spread out over the course of the day and week compared to the pre‐pandemic baseline. Fundamental changes to the diurnal flow profiles of vehicle traffic over the day and week will have implications for transport modellers in areas such as air quality assessment, traffic management and transport planning. Meanwhile, cycling has increased in terms of volume and changed in the time‐of‐day people are travelling. Policy makers need to consider, in the context of net zero targets, how to promote more sustainable transport modes by making use of potential spare capacity on the road network as peak hour vehicle flows become less prevalent.