Bikers and motorists are being reminded extra care must be taken on the roads this Mad Sunday - even though there is a racing taking place on the course this afternoon.
Inspector Derek Flint says whilst the Mountain remains one-way for the entire two weeks of the festival, "Mad Sunday" can lead riders to ride over-enthusiastically and run out of both skill and road.
With good weather forecast a large numbers of cars and bikes are expected to be out this morning before the road closes.
Inspector Flint says officers are totally geared up for this, and will be out at peak strength to quell what he refers to as any "over-enthusiasm" and deal with people who fail to use the road responsibly.
He also points out if there is an accident on the Mountain then the road will be closed - and this could lead to police being the only people up there until racing begins.
In order to avoid this disappointment he says riders must remain sensible and remember Mad Sunday doesn't mean the public roads are a racetrack.