It's the speed that gives the adrenaline high to participants and spectators alike.
But it's also what leads to tragedies such as that which killed two people this weekend.
Try as you might to make rallying safe, it is hard to make a contingency plan for a speeding car somersaulting out of control.
The world of car rallying has always drawn a huge crowd of fans and curious locals as roads are closed and vehicles of all vintages are put through their paces.
It's the speed and the chance to get close to the action that provides the thrill.
Of paramount importance is safety, but the basic problem is that the races take place on public roads.
Formula One races take place on purpose-built racing circuits with large swathes of gravel traps to slow down out-of-control cars, and safety barriers to protect the crowds.
But rallying is different.
Cars regularly become airborne on road humps, and part of the talent involved is going around corners sideways to gain vital seconds.
People always like to view rallying close to corners because that's where the action is.
And because accidents are more likely to occur at corners, you will find that viewing areas are very restricted by the organisers.
But the difficulty remains that a car can go out of control through mechanical failure or human error at any part of the circuit, and once a speeding rally car has lost traction with the road it suddenly becomes a huge and heavy weapon bouncing from bank to bank, or through a fence, or over a ditch.
The Donegal Rally has been particularly blighted by deaths in the past decade.
Two years ago, co-driver Thomas Maguire from Co Meath was killed when the Citroen C2 car he was in crashed down a 500ft ravine during a rally.
Following yesterday's tragedy in Cavan, Motorsport Ireland said every safety procedure had been put in place ahead of the event. Jim Reilly, event organiser with the Co Cavan Motor Club, said all safety precautions had been followed prior to the rally, but admitted that rally car driving was a "dangerous sport".
With two major national championships and many local club single-stage events, rallying is well served by more than 30 clubs that promote events every weekend.
Each promoting club is required to appoint a safety officer, a trained and licensed official, who creates a detailed safety plan for the rally following a template provided by Motorsport Ireland
But still the danger is always there. People still want to get close to the action.