Bus drivers have been handed mini DNA kits to help bring people who spit at them to justice.
The kits contain swabs, gloves and hermetically sealed bags allowing samples to be sent for forensic analysis.
They are to be handed to National Express West Midlands’ 3,500 drivers after a successful trial in Birmingham.
PC Sarah Hipkins said: “Spitting is a disgusting, despicable offence and we will push for common assault charges against offenders.
“Drivers and passengers should not be expected to tolerate it on our bus routes.
“These spit kit devices allow us to obtain irrefutable DNA evidence which helps us track offenders and secure convictions at court.”
Latest figures showed 88 spitting incidents had been reported on regional buses so far this year.
Several offenders have already been traced, including a 24-year-old man who was jailed for 12 weeks for spitting at a driver on a No.17 service in Yardley.