Route des Coutures will be closed to general traffic on weekdays for 30 minutes during school drop-off and pickup times.
The 'School Street' scheme aims to make the area around schools safer for pupils and encourage more people to walk or cycle.
St Martin's trialled the concept for 12 months last year, and the arrangement will become permanent when the school year begins tomorrow (5 September.)
Route des Coutures will be shut between 8.30am-9am and 2.45pm-3.15pm.
Emergency vehicles, cyclists and those accessing properties will still able to use the road during these times.
Road Safety Officer, Paul James, says improving safety for all road users is a part of the State's On-Island Integrated Transport Strategy.
St Martin's Primary School Headteacher, Clare Giles, says this is a positive change.
"As a school, we have promoted active travel for many years, but our children raised concerns about the safety risks they had encountered during pick-up and drop-off times.
Having seen this through from an initial idea to a permanent change, it's wonderful for pupils to see that they can make a positive change in their community now and for generations to come.
Most importantly, our pupils and their parents or carers now feel safer travelling to and from school.
I would like to thank the school community and parishioners for their support with this initiative."
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