The key process parameters influencing modified bitumen versus roll roofing include the type and concentration of modifiers (such as SBS or APP), the temperature during mixing, and the shear rate applied. Additionally, the duration of mixing affects the uniformity of the modification. The choice of base asphalt and the specific application method also play crucial roles in determining the performance characteristics and durability of the final product. Proper control of these parameters ensures optimal properties for roofing applications.