the maintenance and operation cost should be accounted by summing up the maintenance and operation costs in each year which are converted to present values in the base year in the manner explained in "3.4 cost benefit analysis".
If there is an already made maintenance and operation plan of the road the calculation should follow the schedule in the plan so as to determine the year to year cost flow. If not the pattern of cost flow may be selected from the other cases similar in terms of road type,traffic volume,vehicle type composition of traffic, geographical features and climate conditions