The commissioner has the power to revoke Flintshire's operator's licence.
The council faced court fines and costs of£5,000 in January after admitting to a series of offences.
Now the north-west traffic commissioner, Keith Waterworth, has summoned the authority to the public inquiry to be held in April to explain the violations and what remedial action has been taken.
It also appointed a new vehicle maintenance manager and provided extra training for fitters, tachograph training for drivers and training for all staff on how to spot defects.
A council spokeswoman said: 'Flintshire welcomes the opportunity to inform the traffic commissioner of the measures we have taken and to re-affirm our commitment to the safety of our vehicle fleet.'