Eleven private hire vehicles were found committing licensing offences during an operation in Aylesbury.
Three of these were taken off the road with immediate effect, while the others were required to comply immediately or face further action.
The offences included drivers not wearing ID badges and not displaying the correct signs.
One driver was fined £60 and got three points on his licence for having a bald tyre and another was fined £60 for not wearing his seatbelt.
Five prohibitions were applied for serious mechanical defects, with all of them removed from the road until they have been repaired and had a full MoT.
Police stopped 26 private hire vehicles in the town centre on September 5 and checked for defects, while Aylesbury Vale District Council licensing officers checked they had the correct documents.
Sgt Daniel Collett described the operation as a success.