I would like something more catchy like the triangle of death or at least at the same dramatic level, but respecting its author we will use the original term that Randy Pobst has given to this concept with which he tries to explain (and minimize) the dangerous situations and collisions on the track.
And who is Randy Pobst? Well, he is an American driver who races and has raced a lot for companies, magazines, racing teams, coaching sessions and thousands of things related to motorsports. He adds to his facet as a competitor the one of divulgator, and thanks to it his advices and teachings (the one we are referring to) are now part of the rule books of competitions like the North American SCCA.
So let’s get to the point, what is the danger vortex? Let’s see the official document (originals PDF clicking here):
Racing Room & Passing Guidelines
Safe, successful passing is based on what drivers can see. An overtaking car bears the largest percentage of responsibly for passing safely.
Peripheral Vision
The overtaking car (the car attempting a pass) must get into the peripheral vision of the lead car (the car being passed) in the brake zone, before the lead car turns for the corner. Once the lead car turns for the corner, it can no longer see the trailing car, because the lead car’s mirrors now point outside, and the
lead car must now be looking toward the apex.
The diagram above shows that the overtaking car has gotten up to the A pillar and into the peripheral view of the lead car before turn in. The overtaking car now has taken the line away and earned the right to racing room on the inside.
To earn the corner, the overtaking car must have its front end up to at least the A pillar post, or windshield, with the car under control, before the lead car turns into the corner. The goal is for the overtaking car to present itself, to arrive in the peripheral vision of the lead car, before it turns in.
An overtaking open-wheel car should have its front wheel up to at least the lead car driver’s shoulder (within their peripheral vision) before the lead car begins its turn in.
The Blind Spot
The diagram above shows that at turn in for the lead car the overtaking car has yet to get even with the A pillar and into the peripheral vision of the lead car. The overtaking car is in a blind spot. Do not pass, unless the lead car is much slower and gives racing room.
Racing Room
Should the lead car decide to ‘go with him/her’, side-by-side, then both cars must allow each other racing room, at least a car width plus six inches or so, to the edges of the racing surface. In both cases, the trailing car must be in the lead car’s peripheral vision to safely hold position. If not in vision, then the trailing car must back off and follow, because the lead car cannot see it.
The biggest mistake, and a common cause of contact, is the overtaking car taking a shortcut to the apex, from that blind spot. (Turn One at Road Atlanta is classic). Pull parallel to the lead car, and as close as safely possible so that he KNOWS you’re there. Sometimes, the lead car may turn in early; therefore the overtaking car must be under enough control to avoid contact.
Passing on Straights
On straights, the lead car is allowed “one move”. It is allowed to choose a side, but cannot move back, and cannot move over in reaction to an overtaking car if late enough to invite contact. He must leave a car’s width (plus 6 inches) of racing room if the overtaking car has already committed in that direction and has achieved an overlap next to the leader. No weaving to break the draft or to block; that’s more than one move. On straights, as opposed to corner entry, it is possible for the lead car to look into its
mirrors and see the overtaking car, so if the overtaking car gets even a small overlap next to the lead car, the lead car must give the overtaking car room to race, and can no longer move across the track.
When being passed, hold your line. This means be predictable, and do not change your line to pull out of the way. ‘Hold your line’ does not mean take the line for the apex and turn in front when a much faster car is approaching. Be aware of faster traffic, and leave a lane of racing room for them.
The Vortex of Danger
The Entry Vortex of Danger is a triangle inscribed by the turn-in point of the lead car, the apex, and the inside edge of the road. When overtaking, keep out of the Vortex of Danger. It’s too late to pass. The hole you see is closing rapidly, you are in a blind spot, there will likely be contact, and it will be your
fault.
The Exit Vortex of Danger is a triangle inscribed by the apex, the track-out point of the lead car, and the outside edge of the road. When attempting a pass on the outside, be aware of the Exit Vortex of Danger, and back out of it if not in the lead car’s vision. It’s too late to safely pass. The hole you see on the outside is closing rapidly, you are in a blind spot, there will likely be contact, and it will be your fault.
The Outside Pass
On this outside pass attempt, the overtaking outside car never presents itself into the vision of the lead car, and cannot expect it to make room for a car it cannot see at the exit of the turn. So the outside trailing car must back off to leave racing room for the inside lead car that cannot see it, and avoid the Exit Vortex of Danger. In this situation, if the outside car makes contact or runs off the road, it is most likely their fault.
Turn 5 at Road America is a prime example of where a lead car may protect his/her line by not using all of the track on the right. The overtaking car, in this example, needs to assuredly ‘present himself/herself’ in the braking zone before turn in, the lead car is looking into the corner, not at his right mirror, and in all probability will not leave racing room at the exit. Outside passing works well when the both drivers have excellent spatial awareness but is a very low percentage move in most cases.
Safe, successful passing depends on what a driver can see. Do not hit what you can see!
Final Thoughts
One of the finest interpretations of this advice has been done by Ian Korf and it can be found clicking here. Basically the SCCA paper focuses mostly on the chase car, leaving a lot of freedom for the leader to act, but it hints at certain aspects that the aforementioned article by Ian Korf accurately remarks.
- The leading car is the one that marks how big the vortex is.
- Defend on an inner line means to create a smaller vortex or no vortex at all.
- In case of contact on entry, it is safer to being hit on the rear than the suspension or sidewall.
- The entry vortex occurs at high speed and is prone to provoke failure and contact.
- The exit vortex, with less speed is much safer for both.
- Trust and skill of the pursuing driver are keys to the overtaking taking place without incident.
Applying this simple concept to your simracer career (and racing too) can avoid you many headaches.
You can enjoy this FB video of Lucky Dog Racing League where Randy explains what Vortex of Danger is to their fellow racers.
