Drivers and bikers are being reminded not to cross the double white lines on the Mountain Road.
The Department of Infrastructure says whilst a one-way system is in place from Ramsey to Creg ny Baa regular road traffic laws remain in force.
It is therefore illegal to cross solid white lines and rules on dangerous and careless driving still apply.
The Department is again reminding all drivers and riders to remain vigilant at all times, stay well to the left hand side of the road unless overtaking slower moving traffic and to expect the unexpected.
It also points out that unmarked police vehicles are in operation island-wide and anyone signaled to stop by a police officer should do so as soon as it is safe to pull in.
Inspector Derek Flint says the Festival has reached the point where traditionally, the number of fans arriving steps up a gear, and is appealing to riders and drivers not to become "the first big statistic of 2013".