In this article, I will answer three questions:
1) Did Vettel move towards Karthikeyan?
2) Did Karthikeyan move towards Vettel?
3) Did Vettel leave Karthikeyan enough room?
Analysis of the crash:
The confusion for who's at fault and what happened, seems to come from the fact that there are two camera angles from the crash, that each seem to tell a different story. The camera angle from the back makes it seem that Vettel cut across on Karthikeyan, while the camera angle from the front suggests it's Karthikeyan who turns in to Vettel. Now the problem with the rear angle is that it's an angled moving shot, with no static objects in the background to tell us their absolute positions. The front angle however, does provide a static background to analyse the driver's movements.
In the stills, the green line is a control line, following the second L of the blue Allianz board, as well as the border between the green and the white tire wall in the background. As the camera pans a little, we need to adjust the frames so that they still have the same background as a reference. The blue line indicates Vettel's position out of the corner, while the pink line indicates Karthikeyan's position out of the corner.
Frames 1 to 3 show Vettel and Karthikeyan both going in a straight line. However, from frame 4 to frame 6, Karthikeyan clearly starts moving towards Vettel, who keeps going straight. In frame 7, Vettel actually moves away from Karthikeyan, who in turn keeps moving towards Vettel until they collide between frame 9 and frame 10.
As far as Vettel leaving Karthikeyan enough room, it may seem in the first few frames that Karthikeyan will run out of road. However, in frame 5, if you draw the orange line from Karthikeyan's outer tires forward, he has enough room. Between frame 5 and the collision between frame 9 and 10, Karthikeyan still moves over half a car length.
So that answers the three questions:
1) Did Vettel move towards Karthikeyan?
No, from the moment both drivers were through the corner, Vettel kept going in a straight line. He did not move over.
2) Did Karthikeyan move towards Vettel?
Yes, as clearly shown, Karthikeyan actually moves over towards Vettel.
3) Did Vettel leave Karthikeyan enough room?
Yes. Although Karthikeyan was initially going to run out of road, in frame 5, he did not need to move over any further in order to have enough road. However, he still moved over another half car length towards Vettel until they collided.
In conclusion:
The camera angles made it a little unclear on which driver moved how, when and where. With apparant equal blame, the stewards' decision to give Karthikeyan a penalty seemed very odd. While it can still be argued if the penalty was deserved or not, and while Karthikeyan no doubt did not hit Vettel on purpose, a factual analysis clearly shows that it was Narain Karthikeyan who was solely responsible for running into Sebastian Vettel.
