This study introduces and analyzes the use of power function for small scale traffic volume projection. Traffic volume forecasting is an important step in any traffic related study involving analysis of future condition. Projected traffic is always used to determine important highway design elements, urban planning and economic decisions. Accurately projected traffic will lead to a better and more appropriate designed transportation facility, while unaccurately projected traffic may lead to under or over-design of a facility resulting in an insufficient use of public or private funds. The most important part of traffic forecasting is the calculation of growth rates used to project traffic to the desired year. Usually, growth rates are calculated from historical traffic counts or from regional forecasting models. There are deficiencies which has been associated with regular growth rate calculations especially at small scale level. This study introduces the simplified approach for small scale traffic projection using a power function method. Not only that the projection from power function is simple to analyze and interpret, it also can calculate traffic growth rates using data like population, employment, registered vehicles and other available data. The study applies the use of power function to calculate growth rates in two cases; one in which adequate historical traffic data is available but with inconsistent pattern and the second in which no adequate historical data is available. In both cases, power function produced reasonable and realistic growth rates. Traffic projected with power function was split in phases in which higher growths were recorded at initial years, average growth in mid years after implementation and lower gradual growth at the end approaching design year. Thereby forecasting traffic using power function fitted curve can give realistic growths reflecting traffic, land use and socio-economic development patterns.
Abstract