Why is the car drifting to the left in Trackmania Nations Forever

trackmania-forever

In Trackmania Nations Forever on Windows, when I only press the up arrow, my car starts drifting to the left after after it hits the beginning of a slope. Why?

Demo:

Best Answer

As has been covered in the comments, this appears to be a unique quirk of the Trackmania physics engine.

My theory is that when evaluating each frame for collisions, the four wheels of the car are not all considered at the same time, so the jolt received when hitting the sloped booster is registered a fraction of a second earlier on the front left wheel compared to the front right, resulting in a slight difference in imparted acceleration from the impact - which has the end result of the car veering slightly to the left after the impact.