A 33-year-old man was arrested on suspicion of driving over the prescribed alcohol limit following a crash that police said “could have ended badly”.
The collision was among several incidents dealt with by police officers overnight on Friday into Saturday, despite earlier warnings to motorists.
Photographs shared by the force showed a white car beside damaged harbour railings, with debris scattered across the pavement.
Other images showed a section of the harbourside cordoned off and pieces of railing on the sand below.
In an update posted on Saturday, police said officers had also encountered a number of motorists speeding during checks at various locations around the Island.
A further update confirmed that the road safety operation had resulted in 12 referrals for Parish Hall Enquiries and six instances of officers providing words of advice.
The force said a small team had carried out checks and spoken with members of the community across Jersey.
Police also urged drivers to take account of changing weather conditions, reminding motorists that stopping distances on wet roads are at least double those needed on dry surfaces because water reduces tyre grip and friction.
