You show the form of the road load equation to be
F = ½*CdA*ρ*V² + CRR*V*m*g.
This indicates that the resistive force due to rolling resistance is directly proportional to the velocity of the vehicle. I am surprised at this and indeed the online calculator -
Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com indicates that rolling resistance is constant with respect to velocity.
Which is correct?