Bus passengers could be asked to carry out on 'social distancing' on-board as transport bosses trial post-lockdown plans.
Services in parts of the UK are already looking at how services will run safely once the lockdown begins easing.
Prime Minister Boris Johnson is expected to announce some changes as he unveils the plan following a review of the restrictions this Sunday.
Questions remains over whether the government will follow other countries' directions in mandating public transport users to wear face masks or coverings.
In Bristol, a bus operator will ask passengers on one route to carry out ‘social distancing' in a trial revealing how buses could be used in a loosened lockdown scenario.
The trial on the First Bus route began on Monday this week, the Bristol Post reports.
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And it’s expected the measures will be rolled out to the rest of the bus routes in the city soon.
Bosses at First West of England have begun to block off seats on on the 24 bus route and will ensure that people sit apart.
First Bus runs services around the UK, and is one of the largest operators outside London - providing about a fifth of the nation's bus services - amounting to 120 million passenger journeys last year.
Transport bosses have been warning social distancing measures could mean there is not enough capacity to keep operations running.
And London Mayor Sadiq Khan has said he is worried it will be 'impossible' to socially distance in the capital's busy public transport system, including cramped Tube stations.
The First Bus trial in Bristol came as its management warned ongoing social distancing measures would make it impossible for the transport company to maintain enough capacity to keep running.
First Bus commercial director Graeme MacFarlane told the BBC today: "Going forward it's going to be a challenge.
"Because as demand increases and we need to observe social distancing guidelines we do have to put more resource out.
"That means more buses, which is more costly so that is unsustainable in the longer period."
Another operator, Arriva, which runs services in major centres including in Liverpool and around Wales, has already had to reduce services and scrap routes in some parts in response to the pandemic.
Arriva is taking measures like asking passengers to give drivers space when boarding and has encouraged contactless payments.
And in Manchester, transport bosses have announced bus drivers will stop giving change to passengers amid Covid-19 spread fears.
Stagecoach made the change after the Manchester Evening News (MEN) highlighted drivers' concerns.
The city's mayor Andy Burnham cited public transport as a major issue if the PM decides to begin easing the lockdown next week.
The MEN reports Transport Secretary Grant Shapps told northern leaders in a call that hand sanitiser and social distancing could be introduced on buses, trams and trains when the lockdown measures start to lift.
He reportedly suggested the government would look to re-introduce public transport services gradually, rather than all in one go.
Meanwhile, First Bus has announced it had started to increase the number of bus services, ahead of people gradually beginning to return to work if, or when, the lockdown is gradually eased.
At the height of the lockdown, passenger numbers in Bristol dropped by 90 per cent, and bus services were cut back to less than half, the Post reported.
But surveys nationally have suggested travelling on public transport is at or near the top of most people’s lists of concerns.
First Bus Bristol operations boss James Freeman said he was keen to reassure people they were making preparations to make bus travel as safe as possible, as he announced the social distancing trial.
“We are closely monitoring our services to ensure that social distancing is being observed at all times for the wellbeing of our passengers and drivers,” he said.
“Now that we are seeing the first signs of workers returning, we have reviewed our social distancing arrangements on our buses.
“In addition to creating extra capacity at busier times of the day, our new seating pilot on service 24 will act as a visual guide to show customers how they can maintain social distancing whilst travelling by bus.
“If it proves effective in helping both our customers and drivers, we will introduce it to all of our services across the region in preparation for more employees returning to work.
He thanked customers for their cooperation and urged passengers to do their best to follow the seating advice as the trial gets underway.
Mr Freeman added: “We continue to regularly clean all touch points on our buses and our drivers are supplied with protective equipment such as disposable gloves.
“NHS advice is also displayed on our buses reinforcing the need for passengers to follow Government guidance,” he added.
He said First Bus was seeing a ‘small rise’ in numbers of passengers on some routes, and the firm was starting to put back buses that had been cut because of the lockdown.
Increasing capacity is likely to concern bus drivers.
Grieving family members and unions have raised the alarm after the deaths of bus drivers working during the pandemic.
Campaigners have urged for personal protective equipment (PPE) for drivers following dozens of driver deaths in London.
In the capital, the fears for drivers' safety led Transport for London (TfL) to stop front-door boarding and to ask passengers not to sit near the front of the vehicle.
This rendered the services free for the time-being as passengers were told they must board and exit through the middle doors only, where there are no payment facilities.
