Passengers will only be allowed to board London's buses using the middle door during the coronavirus pandemic, Transport for London (TfL) has said.
The changes to protect drivers follow concerns that 26 bus workers in London have died from Covid-19.
TfL had been trialling the changes on 140 buses across nine routes and said it was "confident" it could be extended across the network.
Bus travel on London buses has "plummeted" by 85%, the provider said.
TfL's director of bus operations Claire Mann said that the new temporary measures will come into force from Monday.
"Bus drivers are pivotal in ensuring critical workers like NHS staff and grocery workers can perform the vital roles they do during this national emergency," she said.
"Their efforts are nothing short of heroic and it is essential that we leave no stone unturned when looking to protect them."
Passengers should not touch after boarding and have been asked not to approach the driver.
Existing measures to protect drivers and passengers include signage directing people away from seats near drivers, improved protective screens around the cab and regular announcements reminding those on board of the need to maintain social distancing.
TfL said it was also considering creating a "completely sealed partition" between drivers and passengers.
Yesterday, Mayor of London Sadiq Khan said passengers should be made to wear face masks when travelling around London.
Despite UK public health experts not currently recommending their use, Mr Khan is lobbying for guidelines to be changed.