Abstract:
The purpose of this study was to introduce four truck trip forecasting techniques which were developed from the techniques used in forecasting passenger cars. These techniques were. (1) Truck Short Count Technique. The purpose of this technique was used in estimating the volume of trucks on any road segment. This research was conducted on the road in the urban area by first classifying the roads into different classes according to the number of lanes, lane width, speed and the distance between main intersections, etc. Hourly truck traffic counts were made in order to be used as factors in expanding all the vehicle traffic. Then they were grouped according to hourly interval and classes of roads. The results revealed that the hourly percentage used to estimate all the truck traffic as the expanding factors could be roughly employed to the truck volume on the same classes of roads. (2) Truck Percentage. The purpose of this technique was to estimate and to forecast quickly the truck percentage on a road segment. The studies were conducted in the rural area by classifying the roads into groups based on their functional uses and socio-economic environment. Then the calculations for the trucks percentage and group percentage of all truck traffic were made according to the classes of roads and types of trucks. The results of the analysis revealed that the standard deviation of the trucks percentage was high and that these techniques were insufficient to explain this high values of standard deviation which had happened. However, the percentage could be used in estimating and forecasting the truck traffic. (3) Truck Trip Generation Rate. The purpose of this technique was to estimate the impacts created by changing of land use in different areas and systems of roads. This research was conducted in urban area in the form of aggregated trips. The types of travels were classified as external-internal and internal-external trips. Then the studies were made on trip generation expected to happen due to changing of land use, number of population and the employments. (4) Truck Trip Generation by Multiple Regression. The purpose of this study was to control the aggregated total movement of truck trips. The studies were conducted in the urban area by finding the relationship between truck trips to different types of land uses including the number of population and employment; then by using multiple regression, various models were built up and the regression analysis were made by using computer. The results of the analysis showed that the truck trips were influenced by the land use. The influence factors were found to be residential area, warehouses, institutional areas, industrial areas and retailing areas. The usefulness of the study indicated that the characteristics of the trucks trips were different from the other type of vehicle trips and that for further studies in transportation planning, it is necessary to seperate the truck trips from other vehicle trips.