Coefficient of Kinetic friction as a function of speed

[Kibbel]

I'm modeling a moving cart, and I'm trying to determine if the coefficient of kinetic friction changes as a function of speed. Does anyone know of any literature where this is discussed, or if this happens? I would've thought friction solely depends on the types of materials used.

 

[Nessdude14]

The coefficient of kinetic friction is independent of speed. This may seem counter-intuitive at first, because most objects clearly experience more friction as you push them faster. This is mostly due to increased air resistance.