The Mountain Road is one way from Ramsey to Douglas for the duration of TT fortnight.
It was introduced at the Centenary TT in 2007, to try and eradicate head-on collisions.
Inspector Terry Stephen of the Roads Policing Unit says despite the change, people still need to drive and ride responsibly up there:
Person dies following road traffic collision at Hillberry
Police provide update after incident closed roads in the area
Contractors to start installing 20mph signs in Douglas and Onchan
Infrastructure Minister confirms work will start next week
Accessible bus stops rolled out across Bus Vannin network
Department of Infrastructure says upgrades will make travel easier for wheelchair and mobility scooter users
Road closures in place following incident in Hillberry area
Police response ongoing with Little Mill Road, Cronk-ny-Mona and Creg Ny Baa affected