The National Transport and Safety Authority (NTSA) is inspecting vehicles managed by Hanover SACCO, which operates a bus that was nabbed recently ferrying drunk students.
Sixteen out of the 40 matatus managed by the SACCO have reported to the agency for inspection and a warning has been sent to the rest that they risk arrest.
An impromptu check by The Standard, guided by NTSA officials, revealed the vulgarity, obscenity and utter depravity of the language and images on the buses.
Colourful graffiti shouted bold slogans such as 'Easy Skunking', 'Too fast too Good' and 'You can feel sore tomorrow or you can feel sorry...Just do it', all with overt sexual and criminal connotations.
NTSA Director of Motor Vehicle Inspection Gerald Wangai said no bus under the Hanover SACCO has complied with transport and safety regulations.
"Legal Notice 179 that was issued by the Transport Cabinet Secretary prohibits any graffiti or tint on windows. It also forbids offensive messages on vehicles. Graffiti on matatus is not bad but has to comply with the rules. We have also banned loud music and rude touts," he added.
NTSA now says the SACCO buses may be banned from operating because of what one of their members – the scandalous 'party on wheels' bus – did recently.
"The licence operator of all these buses is the SACCO. If one goes against the rules, then the licence will be revoked and that means none will be allowed on the roads until they have been inspected," NTSA Director of Road Safety Mathew Munyao said.
But an official of the SACCO, Nelson Nzibi, was apologetic.
"We were not very keen as a SACCO but have now learnt from our mistake," he said. Last week, students from various secondary schools in Nyeri County were arrested having sex, drinking and smoking bhang on a bus operated by Hanover SACCO enroute to Nairobi.