Structuring Category Analysis Using Statistical Technique

The transportation‐planning process incorporates the development of representative‐trip‐generation models from base year data for making forecasts of travel in subsequent years. Category analysis is a technique based on the unit of the household and its characteristics. The data are cross‐classified over various socioeconomic schemes. Trip rates based on such schemes are made for a particular category of analysis unit. When the household characteristics are cross‐classified with the available data, certain cross‐classification cells may get sparse data and certain others may not get any data. Under such circumstances, conventional application of category analysis may not be appropriate. To overcome this difficulty a linear statistical model framework was developed. The estimated mean trip rates for the cells of the cross‐classified table use a model fit based on data from all cells and not just the data from any given cell, which may not be reliable. Developed models were illustrated for the different cross‐classification schemes.