New signs have been put up at the north end of Green Street reminding drivers of the new one-way system.
Only buses, bikes and emergency vehicles are allowed to travel southbound from the roundabout, with all other traffic having to find another route to Havre des Pas.
It's after States Members agreed to the change last June, and the Infrastructure Minister - Deputy Kevin Lewis - signed a decision to make a temporary road closure permanent.
However, Police have had to step up patrols in the area, following complaints from residents that motorists were ignoring the new rules of the road.
St Helier Honorary Police officers say they are continuing to monitor the road:
Officers have been present at Green Street this morning monitoring the No Entry restriction.
— St Helier Honorary Police (@StHelierHonPol) February 27, 2020
The signage has been increased to ensure the restriction is clear to drivers.
There have been no offences reported by officers today but we will continue to monitor the road. pic.twitter.com/MhoXy3aYlh

Up to £150 for families to help with school essentials
No more funding from Guernsey for Jersey company that delivers its newspapers
More security for Jersey renters and landlords from today
New plans for £110M Fort Regent revealed
Homelessness in Jersey decreased at the end of last year
Minister shares travel concerns with UK Home Office
Jersey saves almost £45M through external workforce cuts
Bid to expand generation-spanning Jersey dairy farm