Mobility

COVID-19: Is public transport safer than we think?

Woman sits on empty bus with mask on.

Peter Barrett

Posted September 15, 2020

As the world continues to adjust to COVID-19 people are shying away from using public transport. But are the fears justified?

When global finance firm Carlyle issued an edict telling employees not to take public transport to work to prevent the spread of coronavirus, it brought into sharp focus a seismic shift in the way mass transit is perceived in the COVID-age. 

Carlyle’s policy, which also requires staff to self-isolate for 14 days if they catch a train or bus on the weekend, crystallises a pervasive fear that public transport presents a dangerously high-risk environment for infection. 

These fears have spurred a sharp drop in public transport use around the world as cities emerge from lockdown. A recent Traveller Sentiment Survey found 52 per cent of respondents across nine countries were “uncomfortable” using subways and buses.  

In Melbourne, a recent Monash University study predicts an exodus from the metropolitan public transport system, forecasting patronage will recover to just 80 per cent of pre-COVID levels, even as the pandemic subsides. Lead researcher on the study, Professor Graham Currie, told The Age: “Crowding and infection fear are new major concerns for users.” 

The implications for those who plan and live in our cities are worrying. The Monash study found that while many pre-pandemic commuters will opt to work from home, an estimated 9 per cent would ditch the train or bus and drive to work instead. The result could be traffic gridlock.  

It’s hardly surprising that people are wary of crowding onto a poorly ventilated tram or train with scores of strangers in the midst of a pandemic. Yet there is evidence that public transport may be less risky than many of us think.  

A recent Bloomberg article highlighted international research which calls into question a link between public transport and significant COVID-19 outbreaks. In France, the national public health body revealed that not one of 150 clusters of new coronavirus cases between 9 May and 3 June were associated with public transport. Likewise in Japan, Science reported that following the end of that country’s state of emergency most infection clusters were happening in crowded gyms, bars and karaoke rooms – none were linked to its crowded commuter trains.  

And, in Guangzhou, China, a preliminary study of nearly 5000 close contacts found that the risk of transmission on public transport was “low” (just one per cent of the risk of a household setting), and concluded that returning to work or school on public transport was “feasible … on the premise of low personal density”. 

Yet other cities tell a different story. New York’s transport system, for example, has been hit particularly hard by COVID-19, with at least 132 MTA workers killed by the disease. And in London, 37 public transit workers – including 28 bus drivers – have died from the virus. 

Japanese man standing inside train holding onto side.

Most infection clusters in Japan have been linked to crowded gyms, bars and karaoke rooms – none to commuter trains. 

 

So just how risky is public transport?  

Associate Professor Philip Russo, deputy chair of the Australian government’s Infection Control Expert Group for COVID-19, says while travelling on public transport carries some risk of infection, the level of risk will depend on the number of cases circulating in the community. “With the number of cases dropping off then the likelihood of you coming into contact with somebody with the virus decreases as well, because that way we have a safer environment.” 

Good ventilation and universal mask-wearing also mitigate the potential for transmission, says epidemiologist and Professor of Urban Transport and Public Health at the University of Melbourne, Professor Mark Stevenson. “We will need to be using masks on public transit – that’s just how it’s going to have to operate.”  

Many countries, including South Korea, Germany, Argentina and England, have opted to make masks compulsory on their transit systems. And in France, artificial intelligence is being used to check that commuters are obeying the rules and wearing masks (although not to penalise people, say the inventors, rather to “better predict future outbreaks” of COVID-19).  

What other ideas are out there that could make our commute look and feel safer?  

Ultraviolet light cleaning 

New York’s Metropolitan Transportation Authority (MTA) has partnered with Columbia University’s Centre for Radiological Research to trial UV light in nightly disinfection procedures of the city’s subways and buses. Those involved say the UVC radiation is effective on all organic matter, including all coronaviruses, SARS, influenza and Ebola. Enhanced cleaning is already underway on Melbourne’s tram network and will continue to play an important role across all modes of public transport for some time, according to this WSP white paper.     

Check the air  

In her 2011 study on the risk of airborne influenza transmission in passenger cars, Queensland University of Technology expert on dynamic air particles Professor Lidia Morawska found that recirculated air greatly increased the likelihood of transmission. The same principle applies to coronavirus.

“Maximising ventilation and avoiding recirculation is very important. If recirculation cannot be avoided, then proper filtration of the air that is returned back to the cabin needs to be ensured.”

In practice, authorities could gauge how fresh the air is inside our trains, trams and buses using carbon-dioxide monitors and, if necessary, modify air-conditioning systems or install filters. More simply, doors could be required to open at every stop to aid ventilation.

However, no fancy filtration system will stop someone transmitting the virus if they are unmasked and standing 20 centimetres from your face for a prolonged period.

Avoiding overcrowding by enforcing appropriate physical distancing, limiting numbers of passengers on each service or clearly marking where people can sit or stand will be critical. 

Ban talking 

Much of Japan’s early success containing the virus has been credited to its public campaign to avoid the three Cs: closed spaces, crowded places and close-contact settings, including close-range conversations. In Japan, mobile-phone use on public transport is a cultural taboo. So, why not here?

Dr Robyn Schofield, director of the University of Melbourne’s Environmental Science Hub, stops short of advocating a ban on talking, but she does hope people will refrain from shouting and singing in poorly ventilated spaces.

“[There should be] a public awareness that those are going to be high aerosol-generating activities … I think the public on the whole know that.” 

Tram drives past large buildings in the city.

The Monash study found an estimated nine per cent of workers would ditch public transport and drive to work instead, resulting in traffic gridlock.

 

Use technology to detect, predict and avoid overcrowding 

St Pancras International station in London is using technology to monitor physical distancing by passengers in real time.

The system not only alerts station managers to current and future overcrowding (important tools in the battle to keep commuters safely distant) but can tell when passengers are walking or congregating too closely together, and thus spark a pre-recorded public announcement.

It may sound like another brick in the Big Brother wall but OpenSpace, the UK startup behind the system, says the data collected is anonymous and facial-recognition technology is not used.

Sydney’s rail network already uses technology that shows commuters real-time seat availability and predicts public transport delays.   

Permits for peak-hour workers 

As public transport operators strive to ensure appropriate physical distancing, extending peak hour is going to be vital. One way to do that is to follow the Paris Metro’s example and issue travel certificates to workers who must use the system at peak times. These could work in a similar way to permits already issued in Victoria under the Permitted Worker Scheme.

Meanwhile, transport authorities could ask business leaders to stagger work times for employees, as the MTA did in New York in May, and discounts could be offered for off-peak travel, as has happened in NSW.

Thermal-image testing at stations 

Thermal-imaging testing – measuring a person’s body temperature with a specialised camera – has been tried on commuters in New York City and Bilbao, in Spain.

If an individual has a temperature above 38 degrees Celsius it might indicate they have a fever, a common symptom of COVID-19. At that point they may be refused entry and told to seek medical help.

But the effectiveness of this tool is very much in doubt, with questions over its accuracy and inability to spot asymptomatic cases.     

Buses on demand 

The gradual easing of restrictions in stages means certain groups will start using the system before others. Public Transport Users Association spokesman Daniel Bowen says while many CBD-based white-collar workers may continue to work from home, initial demand will come from schoolchildren and blue-collar workers travelling across the suburbs rather than into the city centre. That means greater demand on the bus network.

“It’s going to be important for the government to watch levels of patronage on bus services and address any issues around physical distancing.” He says patronage data from the Myki system and the greater flexibility of bus timetabling means the government could quickly invest in more services where needed.  

Michelle Batsas, executive director of the International Association of Public Transport (Australia and New Zealand), says some public transport operators are trialling new services to better balance demand and supply of transport options. For example, in China’s Shenzhen people are using “on-demand” bus services, where passengers book local trips on smaller shuttle-bus services via an app.