A new 50mph speed limit will be introduced on the Coast Road during this year's TT fortnight.
It's in a bid to reduce the number of crashes between Douglas and Ramsey – and to stop motorists using it as a loop road back to the Mountain Road section.
Officers will patrol the route using unmarked cars and bikes.
The move was announced yesterday during the launch of the 2018 road safety campaign.
This year the slogans being used are: Keep Calm and Slow Down, Keep Calm and Ride Safe and Keep Calm and Drive Sober.
Chief Constable Gary Roberts says: "The TT period is a time for the Island to host and entertain many thousands of people, in addition to their vehicles, and this brings a range of challenges in keeping people safe.
"Officers will be highly visible throughout the festival - both on the roads and on foot patrol at many events - and look forward to playing their part in ensuring the safety of visitors and residents."
The one-way system on the Mountain Road will be in place from May 25th for the entire fortnight.
Home Affairs Minister Bill Malarkey says: "The number of people visiting Manx shores during TT always places extra demand on the emergency services, and I urge people to heed the message behind this year’s campaign: to stay calm and think of others.
"The festival is a great sporting spectacle and it's vital we are able to minimise the dangers posed by increased volumes of pedestrians and traffic on the Island's roads."