[yelsew]

I have no idea If the engineers had this consideration when designing the dynamics of the car, but this is an excerpt from an SAE paper on racecar vehicle dynamics.

"When selecting the track width, the front and rear track widths do not necessarily have to be the same. For example, track width is typically wider in the front for a rear wheel drive race car. This design concept is used to increase rear traction during corner exit by reducing the amount of body roll resisted by the rear tires relative to the front tires [4]. Based on the corner speeds and horsepower to weight ratio of FSAE cars, this concept should be considered by the designer".

So perhaps this was part of cars design

EDIT: okay scratch everything I just said...I looked up the track width of our cars and the rear is actually wider than the front, and it is the fender that is wider on the rear... and I don't know what that purpose is, most of aero and body design are beyond me