Once we've been given a ticket, we would at least hope it was issued honestly and in good faith.
But a new documentary or BBC One finds that sometimes isn't the case.
A BBC journalist, Nkem Ifejika, went undercover to look at the procedures being used by parking wardens in one London borough.
He worked as an attendant for a contractor used by Kensington and Chelsea. And what he found was shocking.
She heard from the team who made the Whistleblower programme - and from the parking trade's governing body
In the UK, a parking ticket is issued every five seconds. Fines now raise more than £1bn a year for councils and the private contractors they employ to carry out their parking services.
Motorists claim they are often incorrectly penalised for the slightest infringement.
As well as battling traffic, and finding parking spaces, many live in a state of fear of being issued a ticket, clamped, or towed away.
Whistleblower uncovered a shocking culture of illegal procedures including parking attendants cancelling tickets for cash in Westminster.
There was even one example of attendants attempting to steal a motorbike.
The BBC has put these allegations to the parking firm involved, APCOA. In a statement it said:
"To date, we have not found evidence to support the BBC's allegations. In the absence of such information, we believe that the incidents referred to...are at worst isolated events.
"The overwhelming majority of our PAs and managers are hard-working, diligent and responsible people doing a difficult job very well."
If you feel you've unjustly been given a ticket, you can appeal to the official independent parking adjudicators.
We've provided you with links to the official appeals websites on the right hand side of this story. There are also other unofficial websites, run by campaigning groups, which can provide help and advice.