How many tyres do you think Mr - that the defendant would have needed to set up on the day of - that this go karting event took place?---In the whole perimeter of the outside of the track you'd need hundreds.
Hundreds, and you'd need them two high, so you'd need hundreds?---You would need - I think my own view is one height tied together because the reality is that the kart impacts at the height of one high. So it depends how you would prioritise the exposure, the least energy absorbing structures are the tree, next, the least energy absorbing structures are the posts and then the kerbs present a particular risk for at the northern end, for someone driving straight into it but on the eastern end that in my view it would be more for a side impact and ejection of the person.
So you'd need hundreds of tyres and you'd need to prioritise where you put them?---If you wanted to - yes.
And - - -
SCHOOMBEE DCJ: Sorry. Could I just ask, Mr Kahler, are you saying in your view there should have been a line of single tyres right around the track or are you saying that it should have been more than single tyres or are you saying it should have been in certain spots?---Single tyres, your Honour, particularly on the east western boundary and single tyres particularly on the northern end because there is a vertical place in the kerb, the southern end has had other barriers installed which I assume - I - I don't know if they did - they shouldn't have water in them, pin them together and then your next exposure is on the eastern face where the marshal is, but there may be more opportunity for control on that face.
All right? But the western face and the northern face would be the priority.
MANGAN, MS: And this may - I know the accident happened on the straight, but normally if people are going to leave the track or lose control, it's on the bends, isn't it?---It's where the loss of control can be initiated and the trajectory of the kart can take you beyond the corner.
So in this case, the corner seems to be irrelevant because the plaintiff came out of the corner and then after, when she was on the straight, lost control and then pressed the accelerator and went into the tree. Is that - - -?---The corner is relevant in that it sets up the steer angle that he person has chosen, so they're still holding that steer angle as they come out of the corner because the bitumen is wide enough to allow them to do it and go wide. So they're still in a corner. They're just not in the formal corner at the northern end.
But when it comes to prioritising, a person planning this event, we know this accident happened and it can colour our view of what could occur, but before you've seen this accident and you're prioritising, you would put the - most of the barriers you would concentrate on the - on the corners, wouldn't you?---I would do the western face and the northern face because barriers were already installed on the southern face.
Okay. Well, we're going back to scratch. We're planning this event. We're going to use tyres instead of what we did use. We prioritise the kerbs, the corners?---I just (indistinct) the corners are a priority, as well as the western straight. I don't know why you would elevate the corner over the western straight.
...
So you'd have hundreds of tyres you'd need to stack some of them [two] high?---I consider that with the speed of the karts that are involved tied together at one high would have provided the energy absorption capability, separating them in distance from the structure you don't want impacted.
And now, it's a one-off event. At the end of the day you've got hundreds of tyres on your hands?---Correct.
And isn't it the case that that is an enormous problem with disposal?---You have to determine in terms of where you get your tyres whether those people will take them back and you have to consider it in the whole task. Do you get permission from a local authority to take them to a landfill site? These are just the logistics of the planning work. (emphasis added)