Urgent talks are to be held in the wake of attacks on buses in Dundee.
Fears have been expressed that lives are being put at risk amid potentially “fatal” incidents.
A bus driver was injured when a stone was thrown at his vehicle last week.
The missile smashed the windscreen of the 73A Stagecoach service travelling from Ninewells to Carnoustie as it drove along Monifieth Road, Broughty Ferry.
And last month, two youths threw a traffic cone from the roof of a multi-storey car park, shattering the windscreen of an Xplore service at Meadowside.
Officers said the “reckless” act could have resulted in serious injury or death.
Bus company bosses are to meet trade union Unite to discuss how to tackle the issue.
Brian Copland, Unite representative for bus drivers, said: “This is an escalating problem and of increasing concern to our members. The safety of our drivers and their passengers is at risk.
“Our first priority is their safety. We are currently in talks with the bus companies, our members and the police to work out the best methods of keeping everyone safe.”
North East councillor Brian Gordon, a former bus driver, described the actions of those responsible as “extremely dangerous” and said the lives of drivers and passengers are being out at risk.
He said: “These violent thugs are dicing with death by creating potentially fatal distractions for drivers.”
A spokeswoman for Xplore Dundee said the level of antisocial behaviour faced by drivers and customers in some areas of the city was an “ongoing concern”.
She added: “Xplore Dundee’s managers continue to work closely with union representatives, community wardens and Police Scotland as well as schools and the local safety partnership to educate young people about the potential consequences.”
A spokesman for Stagecoach said: “We’re working with the police in trying to identify those responsible for the recent incidents.”