The Department of Infrastructure says it'll introduce temporary speed limits on parts of the Southern 100 course next month.
In order to carry out work before racing begins, there DOI says there'll be a 40mph limit on the course in Castletown, Arbory and Malew.
The Castletown Bypass will also see its limit lowered from 50 to 40.
The restrictions will run from 6am on Tuesday, May 7 May until 6pm on Friday, May 10.
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