This study is carried out to estimate the operating cost of commercial heavy trucks of Fatuha, Bihar. Operating cost is the cost incurred to operate the truck. Only variable costs are considered to calculate operating cost. Variable cost includes salary of driver and attendant, maintenance cost and fuel cost. Maintenance cost includes tire depreciation, wear and tear of spare parts and lubricant cost. A questionnaire survey form was prepared that consisting of eighteen questions to take responses of the truck drivers of Fatuha. Total of one hundred nineteen responses were taken. Three models namely as linear multiple regression model, Cobb-Douglas model and Translog model are calibrated using taken responses. Results show that Cobb-Douglas model is best suited for the study, among all the three models based on R-square and p-value. Operating cost of the truck per km and per tonne km resulted as Rs.20 per km and Rs.1 per tonne-km. In spring season, load carrying capacity of trucks reduces due to bad condition of road. Whereas, 40% changes the route that followed to deliver the goods, 36% reduce the weight per vehicle and 24% shift the delivery time of the goods.
