THICKNESS OF THE PAVEMENT INCREASED FOR HEAVIER LOADS AND LARGER TOTAL VOLUME OF TRAFFIC, AND THE COMPUTATION OF TRAFFIC FOR CBR IS NECESSARY.

Recent rains and intensity of rain fall occured in the Hilly areas of the state of Himachal Pradesh has shown that the widening of hill roads disturbing the system of existing road net work facilitating the people of state and the tourists hubs like Manali and Narkanda Shimla Himachal Pradesh as well as Dharamshala creating problems to the life and liberty.As such it is necessary to avoid construction of more and more four lanes ,divided highways for which the state government and the National Highway authority of India must link this facilitation with the provisions of Two-lanes 7.0 metre carriage way and the 5.5 metre carriage way suggested for the Major District Roads.The development criterion should not be restricted for the welfare of society and circle however at the same time the government and the construction agencies of the roads must follow charter of the road capacity and the traffic count - equivalency factor for vehicles per day (both directions) before raising the classification of existing road capacity and it's improvement based on the CBR method of design and scope of the available methods of the pavement of design for which the CBR method has been found the most reliable as required for evaluating the strength of the sub grade (bearing capacity of the soil) and construction materials,as well as estimating the required thickness of pavement to satisfy a given loading.It is the most convenient and the widely used, though devised for the design of flexible pavements, the method is also used to determine the total thickness of a concrete pavement and granular base of sub -base .CBR is a measure of the load carrying capacity of any soil or granular material, which is expressed as a percentage of the load carrying capacity determined by a penetration test.Computation of traffic for the use of CBR is necessary for which the design is based on the total number of commercial vehicles per day in both directions multiplied by the Equivalency factor.Basic capacity of a traffic lane is the maximum number of passenger cars that can pass a given point on a lane or roadway during one hour under the most nearly ideal roadway and traffic conditions that can possibly be attained.The thickness design of pavement involves the interplay of several variables,such as the wheel load and it's impact effect, volume and character of the traffic expected to use the road, bearing capacity of the soil on which the road is to be built.When a wheel load is applied to the pavement,the intensity of stress reduces as the depth increases from the top of the surface.Thickness of the pavement is increased for heavier loads and a larger total volume of traffic.