The union representing Bus Éireann drivers fears one of them could be killed amid a spate of serious assaults in Dublin.
A female driver was attacked at Busáras on Thursday as she got ready to drive a 6am bus to Belfast.
The National Bus and Rail Union says its members are targets for violent thieves looking for cash.
Spokesman Stephen Nugent, says they want safety screens fitted to the coaches so they have the same protection as Dublin Bus staff.
"It is extra shocking when a female member of staff is attacked," he said.
"Are the government only going to react when some driver is killed?
"Is that what it's going to take to get one of these safety screens fitted?" he said.