The Transport Workers' Union has called on the South Australian government to do more to prevent violent attacks on Adelaide's bus drivers.
The union says public buses have become a "hotbed of violence and abuse".
It says in one recent attack a bus supervisor was put in a headlock and kicked repeatedly at a suburban interchange.
"Assaults against drivers are happening every day. Drivers are being abused every day," union state secretary Ian Smith said.
"Physical assaults, verbal abuse, being spat on - it's absolutely disgraceful."
The union has urged the government to increase the police and private security presence across the network and introduce extra security at all major interchanges.
It also wants the installation of full driver protection systems, including safety screens, on all buses to protect drivers.
