Matatus and buses can have graffiti as long as it is not offensive and does not extend to the windows.
National Transport and Safety Authority Director-General Francis Meja on Monday said the law allowed matatu owners to use innovative decorations, including pictures, words and symbols.
He, however, said they should not be offensive or have reflective properties.
“Windows should not have any decorations. Sacco names should also be visible,” he said.
Mr Meja added that operators were allowed to install TV screens in vehicles but warned that action would be taken against those airing offensive and obscene content.
“We shall have special undercover teams to monitor what is aired,” he said.
He was speaking on Magadi Road on Monday during the crackdown on public service vehicles (PSVs) with offensive graffiti, noisy exhaust pipes and those playing loud music.
He said the operation would continue until order was restored.
In Mombasa, drivers and conductors whose vehicles were impounded complained that they were not told how much graffiti was allowed on matatus.
They said the President had allowed vehicles to have graffiti.
Mr Meja, however, said the crackdown did not go against the President’s 2014 directive.
“NTSA and the Transport ministry came up with a legal notice allowing for innovative graffiti but with clear conditions,” he said.
According to the Act, the decorations could be pictures, words, or symbols on the body of the matatu.
“Having many lights on the body of the vehicle can be risky because other motorists may not notice that the car wants to turn in a particular direction,” he added.
In Mombasa, 30 matatus were seized. However, a majority of matatus with graffiti were on the road.
“We have impounded almost 28 vehicles. Many of them had minor problems which could be rectified fast,” Coast Traffic boss Solomon Njuguna said at 1.30pm.
Drivers complained that traffic officers were demanding bribes from them.
“An officer arrests you at Likoni and asks for Sh1,000. When you get to another point, another one demands money,” Mr Mbaji Hemed, a driver who plies the Likoni-Bombululu route said.
Mr Njuguna said he had not received any complaints from matatu drivers or conductors.
In western Kenya, transport was disrupted when matatus kept off roads.
NTSA and traffic officers patrolled main bus terminuses and key roads like the Kakamega-Mumias, Kakamega-Eldoret and Kakamega-Webuye-Kitale roads.
Mr Samuel Lichungu, an official of Kabras Sacco, said drivers who had applied for licences and had not received them were being harassed.
The NTSA said about 60 per cent of PSVs had complied with the regulations. By evening, the NTSA had not released the vehicles seized.