This research paper dealt with Pavement Condition Index (PCI), deterioration of roads, effect of Cellulose Oil Palm Fiber (COPF) modified bitumen binder and complex shear modulus (G*). The PCI is an indicator of the condition of roads, and the value of PCI ranges from 0 to 100. Based on this value, road managers/authorities are able to decide one of the rehabilitation strategies for maintenance of the roads in managing pavements aiming with the lowest life cycle cost (LCC). Rutting deformation and fatigue cracking are the two most common distresses of roads and highways. Bitumen binder used in road construction due to its viscoelastic properties and this property of neat bitumen is inadequate to tackle the rutting deformation and fatigue cracking for the heavier axle loads. COPF is one of the bitumen modifiers used in highway industry to eradicate the deterioration of roads. The main objective of this study was to investigate the effect of various COPF content on the rheological properties of 80-100 penetration grade bitumen. The COPF was blended in ratio of 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0% by weight of bitumen binder. The 0.4 to 0.6% COPF content showed better complex shear modulus (G*) values in all aging conditions and test temperatures considered. The maximum temperature, beyond which rutting deformation will occur, is 640C for modified 80-100 un-aged and short term aging binder. This study concludes to modify bitumen binder with COPF upto the required viscoelastic values to arrest the deterioration of roads.