Modelling the exposure risk tradeoff between public transit and private paratransit for transport decision making in the era of COVID19

  • Wadud, Zia (PI)
  • Leeds, University (CoI)

Project Details


This project aimed to provide a science-based answer for transport policymakers in developing countries to the questions – a) which is the safest publicly available transport mode (including paratransit modes) to move people during an epidemic, b) how to make travelling in paratransit modes – especially motorcycle taxis – safer, and c) how travel choices and preferences have changed during the pandemic?

By developing Computational Fluid Dynamics (CFD)-based models of droplet
dispersion in different types of public transport (buses), microtransit (microbuses-matatus, human haulers) and paratransit (motorcycle taxis-bodabodas/okadas, autorickshaws) vehicles with different geometry, seating configuration, ventilation properties, occupancy and protection (e.g. helmet in motorcycles), the project provided a world-first insight into passenger risks of exposure in these very different types of modes.
The objective risk measures were complemented by a stated preference
questionnaire survey of transport users in the project countries to understand passengers' travel behaviour and reveal their current and future preferences regarding different transport modes.

Key findings

1. CFD simulations predict the presence of a strong down draught of air between the driver and passenger which ultimately determines the fate of the virus-carrying aerosols depositing or being inhaled by the passenger. The draught let the aerosols flow nearer to the passenger’s inhalation zone.
2. Questionnaire survey responses of public transport and paratransit users show a strong preference toward measures to enhance COVID-19 related safety measures, such as maintaining distances, wearing of facemasks by other passengers and presence of hand sanitization facilities in buses, or adding passenger shields/barriers (as above) and cleaning of helmets in motorcycle taxis. While travel costs, time and convenience were the most important factors in mode choice pre-COVID-19, distancing in buses and face-mask wearing
by all passengers became equally, if not more, important during the pandemic.
Especially in Dhaka and Owerri, COVID-19 related safety measures were more important compared to traditional mode choice factors during the pandemic.
3. Choice experimentation and subsequent modelling show that respondents were willing to pay extra for safety measures such as distancing (half capacity seating) or hand sanitizers in buses or shields (as explained earlier) or frequent helmet cleaning in motorcycle taxis. This shows that there is a potential market for safety, and transport operators could potentially pass on the costs of these provisions to the passengers and defray some of the costs, or could compete on the basis of safety features.
Effective start/end date27/10/2026/10/21

Collaborative partners

UN Sustainable Development Goals

In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):

  • SDG 3 - Good Health and Well-being
  • SDG 10 - Reduced Inequalities
  • SDG 11 - Sustainable Cities and Communities


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