The Scottish Government is to reveal its plan on how people can get around when lockdown restrictions are finally eased amid fears that public transport could become crowded.
Labour has warned that trains and buses must have screens and other safety measures in place to protect staff and passengers.
The use of face coverings on public transport could become mandatory under this plan, but it is currently unclear if masks will be handed out to passengers.
Tranport secretary Michael Matheson will make a statement to MSPs tomorrow on the issue.
The need to ensure physical distancing means capacity on individual buses and trains will be around 10% to 25% of usual numbers.
When the lockdown was eased in England earlier this month, Tubes and buses in London were packed with commuters
Scottish Labour's transport spokesman Colin Smyth said such scenes must be avoided north of the border.
He said: "Passenger numbers are already beginning to rise, and that will accelerate as the lockdown is eased from this week.
"We cannot have a repeat of the scenes we saw in England with overcrowding, as people went back to work.
"It's clear the Government has no intention of implementing physical changes on our buses and trains such as removing seats, so they need to spell out how they will actually achieve social distancing in a way that is enforceable and safe for passengers and workers."
He continued: "That has to include assurances that the resources will be provided for physical safety measures such as screens.
"The Government also needs a more definitive position on face coverings. If passengers are being told they must wear them to travel, then they should be available free at stations and stops.
"If the Government has no intention of providing PPE in a comprehensive way for transport workers, then we need to know how they will be protected.
"There are serious questions about how the Government is going to keep passengers and staff safe, and Scottish Labour will continue to demand answers."
A Transport Scotland spokesman said: "The plan will be dynamic and regularly updated and will be aligned to the route map to transition out of lockdown set out by the First Minister last week.
"We have been engaging with a wide range of stakeholders in its development, including operators, Cosla, unions, regional transport partnerships and other stakeholders.
"We know that capacity on our public transport system will remain limited as a result of the need to maintain physical distancing and guidance for public transport users and operators is a key element of the plan to keep public transport safe."
He continued: "This guidance is one of a series being issued by the Scottish Government across different sectors.
"It will assist transport operators and their workforce in the provision of safe operations during the coronavirus pandemic.
"It will also set out advice for users, businesses and organisations when considering when to travel and how staff will travel to work, as we transition through the phases of the route map."
