Bus drivers across the West Midlands have been given 'spit kits', mini DNA devices to help police track anyone who spits at them or fellow passengers.
The kits given by police are made up of swabs, gloves and special bags allow staff to collect saliva samples to be sent for forensic analysis.
So far this year there have been 88 reported cases of people spitting on regional buses.
Following a trial on Birmingham City Centre buses several offenders have already been traced including a 24-year-old man who was jailed for 12 weeks after spitting at a bus driver.
"Spitting is a disgusting, despicable offence and we will push for common assault charges against offenders.
"This type of DNA processing has been used on the railway previously and our trial has been successful. Drivers and passengers should not be expected to tolerate it on our bus routes and these spit kit devices allow us to obtain irrefutable DNA evidence which helps us track offenders and secure convictions at court."
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Duller conditions moving back towards the coast through the morning, leaving a mainly dry day with warm sunny spells.
Showery outbreaks of rain will become more widespread through Thursday with heavy and locally thundery downpours possible.
Pollen: West Midlands Update