Face coverings are now compulsory on public transport as Scotland continues to ease its way out of lockdown.
Children under five and people with certain medical conditions are exempt from the new rule which comes into force on Monday.
It covers buses, trains, the Glasgow Subway, Edinburgh trams, aircraft, enclosed areas onboard ferries, taxis and private hire cabs.
The Scottish government is also urging people to continue to limit travel.
Last week, First Minister Nicola Sturgeon said face coverings “can help to reduce the risk of transmission” but stressed that physical distancing, hand washing and “good hygiene” were still necessary to prevent infection.
Further changes now coming into effect include dental practices being able to see patients with urgent care needs.
Places of worship will also reopen for individual prayer and professional sport can also resume behind closed doors.
In addition, the construction industry will be able to move to the next phase of its restart plan.
But it will be another week before some shops can reopen while the tourism and hospitality sector will need to wait until 15 July to resume trading for the first time in almost four months.
As the transport changes take effect, ScotRail confirmed that masks would be available at 18 of its busiest stations for a limited period.
David Simpson, operations director, said: “The position on face coverings is now absolutely clear and we are urging customers to take collective responsibility and follow the Scottish government rules on their mandatory use.
“But Scotland’s Railway can’t guarantee physical distancing at all stages of a customer’s journey.
“The message remains the same as it has been since the start of the pandemic: only travel if your journey is essential.”
Transport Secretary Michael Matheson appealed to people to leave space on buses and trains for the elderly and needy.
He also urged employers to carefully manage their phased returning of staff to work, with figures suggesting that up to 55% of employees could travel to their normal workplace in phase two, which started on 18 June.
When Scotland was in full lockdown, the figure was just 30%.
This could also result in an increase in the number of passengers on public transport by about a third from the current levels of an estimated 225,000 per day.
Mr Matheson said: “We are now in a position to enter phase two of the route map, however we must do so with great caution, as we cannot risk a resurgence of the virus and wasting all of the good work to date in terms of respecting boundaries and working from home.
“Transport has a vital role to play in helping restart the economy, but there is a clear and great need for personal and collective responsibility when travelling, especially by public transport.
“It’s also very important to leave space on public transport for those who need it most.”
His remarks come after announcing a further £46.7m of funding available to bus operators on Friday.
It will cover any loss of fare-paying passenger revenue anticipated because of the physical distancing measures and reduced capacity on vehicles, which is estimated to be about 10 to 20% of normal.
Mr Matheson added that there would be circumstances when the two-metre rule was breached, even temporarily.
He added: “That is why all passengers have to wear a face covering.
“I continue to engage directly with business leaders and major employers and I am encouraging them to embrace these changes which can help us all adapt to a new working and business environment.
“We are increasing the frequency of public transport, but without a significant reduction in demand, the plan won’t work.”
Meanwhile, the dental development is only for treatments which do not create aerosol particles, which is what happens when dental drills are used.
Scotland’s chief dental officer Tom Ferris said: “Dental practices will be able to see NHS patients who are in need of urgent care for face-to-face consultation, using procedures which limit the risk of spread of using coronavirus such as non-aerosol-generating procedures.
“This will mean up to an additional 10,000 appointment slots available per day across Scotland.”
Latest figures published by the Scottish government reveal that 18,156 people have tested positive for Covid-19.
The number of deaths by that measure is 2,472 but last week’s National Records Scotland figures put the total at 4,000.