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London bus drivers look set to be better protected from coronavirus after experts made changes to the ventilation system.
Engineers found a way to circulate fresh air into the driver's cab from outside rather than inside.
The work by Grayson Thermal Systems was part of a series of measures taken by TfL to protect bus drivers against Covid-19.
"The loss of London bus drivers to the pandemic is tragic and we were pleased to be part of a solution to build on TfL's existing safety measures to reduce the potential spread of the virus," said Ian Hateley at GTS.
"We looked at our existing air conditioning systems and developed a way of converting them so that they created positive pressure in the enclosed driver cabin, forcing existing air out and replacing it with air from outside the bus," he added.
The company's team of engineers took three weeks to come up with the prototype and was invited to convert 2,000 buses over a two-month period.
It means all 9,300 buses in London's fleet meet TfL's strict driver safety guidance and new specifications.
"We always put the safety of our bus drivers first and making changes to the driver cabs, along with other measures like our enhanced cleaning regime, has played a role in minimising risk of infection," said Tom Cunnington, TfL's Head of Bus Business Development.