COVID-19: Reducing the Risk of Transmission on London's transport vehicles

Lead Research Organisation: University College London
Department Name: Civil Environmental and Geomatic Eng


We have much to learn about how COVID-19 has spread, however it is clear that being close to an infected person is a risk. The virus causing COVID-19, SARS-CoV-2, can be transmitted from one person to another through the air, by direct contact or via inanimate objects. The risk of transmission becomes higher the more people come into contact with each other as well as how long this contact lasts. Governments across the globe have enforced measures which aim to minimise person to person contact, including the transmission of saliva droplets carrying the virus. Public transport vehicles are spaces where the risk of transmission is high because a lot of people use them. London's underground and bus network runs millions of journeys daily and is running at a lower capacity during COVID-19 to minimise risk to passengers and staff. However, it is virtually impossible to maintain the 2 m distance recommended in the UK within the public transport system. This project will combine staff and passenger surveys, microbiological sampling, air flow computer simulations, passenger crowding and ventilation models and air quality measurements to better understand how the risk of transmission can be minimised on London's transport systems.


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Description The work carried out so far has shown that amendments to the driver assault screens lower exposure of drivers to the air in the bus passenger saloon.

Microbiological sampling of buses and train carriages has highlighted contamination hotspots and quantified microorganisms in the vehicle air. This has been shared with TfL and their policy has been amended accordingly. The microbiology data is now being correlated with CCTV analysis of passenger numbers and touch points on the sampled trains.

Air quality on buses has been collected over a long period of time and has identified specific conditions (e.g. routes, bus models) that pose a higher risk of airborne transmission.

Computational modelling of the double decker bus has identified the air flows and velocities and locations of stagnant air.
Exploitation Route Data is still being analysed and there are many more outcomes to be achieved over the coming months. The outcomes so far have been shared with the Department for Transport and bus and train operators around the UK. Once the data has been fully analysed it will be presented to TfL and then prepared for publication in peer-reviewed journals.
Sectors Aerospace, Defence and Marine,Healthcare,Transport

Description TfL has used the project finding to make changes to their vehicles in order to improve driver safety and ventilation. The work has also been used to aid decision making on the wearing of face coverings for staff and passengers. The project team has participated in international workshops on the subject of minimising airborne transmission on public transport and published a number of media articles on the subject.
First Year Of Impact 2020
Sector Environment,Healthcare,Transport
Impact Types Societal,Economic

Description Participation in the US National Academies Science Engineering and Medicine "Indoor Air Management of Airborne Pathogens: Public Transportation"
Geographic Reach Multiple continents/international 
Policy Influence Type Influenced training of practitioners or researchers
Description We have been doing with the TRACK project at DfT to influence policy. TfL has also used our research results to make decisions on staff and passenger safety.
Geographic Reach National 
Policy Influence Type Participation in a guidance/advisory committee
Impact Our work has led to the reduction of SARS-CoV-2 transmission to bus drivers in particular, as well as passengers on TfL vehicles.
Description Airborne Infection Reduction through Building Operation and Design for SARS-CoV-2 (AIRBODS)
Amount £1,256,284 (GBP)
Funding ID EP/W002779/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 02/2021 
End 12/2022
Description TRACK project 
Organisation University of Leeds
Country United Kingdom 
Sector Academic/University 
PI Contribution UCL VIRAL and the TRACK project led by the University of Leeds and supported by the Department for Transport are working together in a complementary way to make sure we answer as many questions as possible and do not replicate experimental work.
Collaborator Contribution UCL VIRAL and the TRACK project led by the University of Leeds and supported by the Department for Transport are working together in a complementary way to make sure we answer as many questions as possible and do not replicate experimental work.
Impact This is a multidisciplinary collaboration including microbiology, infection control, air quality, fluid dynamics and behaviour change.
Start Year 2020
Description Transport for London 
Organisation Transport for London
Country United Kingdom 
Sector Public 
PI Contribution The UCL team has worked closely with TfL to monitor environmental contamination, air quality, ventilation and passenger numbers in order too better understand transmission of SARS-CoV-2 on public transport vehicles. TfL have provided data, including confidential and personal data for the research to take place. Research outcomes have already informed ventilation strategies on TfL buses and cleaning regimes.
Collaborator Contribution TfL have provided data for the research project and have facilitated access to vehicles. They have also helped us shape the research.
Impact The project website can be found here: A number of outputs have been listed. The most important one at this stage is the bus driver safety report:
Start Year 2020
Description Participated in indie_SAGE Weekly Briefings 29th July 2022 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Some results of VIRAL research were presented and discussed at the oneline webinar open to the public.
Year(s) Of Engagement Activity 2022