Knowledge discovery can suggest the relationship between variables it contains using as few probability assumptions and linear structural relationships as possible. This information is usually contained in a series of rules that when they are evaluated

to be true suggest a definite outcome. These rules can be expressed in the form of IF-THEN statements or in a tree-like structure. AG-1478 153436-53-4 In this tree structure the internal nodes are decision tests; branches are paths from these decisions and terminal nodes are the outcome [4]. Other representations of the relationship between attributes in the data are also possible, including Bayesian networks [5] and neural networks [3]. In this paper, the knowledge is contained in the form of IF-THEN clauses. The technique for concluding these rules comes from the area of fuzzy set theory and in particular the rough sets application of this theory [6].

The characteristics of interest selected for the application of this theory are the travel mode choice of an individual for a trip. Several recent studies of applying rough sets theory to travel behavior modeling [7–9] demonstrate the good benefits on prediction performance. However, existing researches mainly focus on long distance intercity travel analysis and few of them have compared the method with traditional MNL model. The primary objectives of this paper include (a) investigating the capability and performance on mode choice modeling of urban diary travel using rough sets theory, (b) figuring out the significance of condition attributes on mode choices, and (c) to comparatively evaluating the performance of rough sets model and MNL model. 2. Determinants of Travel Mode Choices The most consistently quoted determinants of travel mode choices are individual demographics, including age, gender, education level, employment status, and availability of driver’s license [10–14]. Young and elder individuals are more likely to utilize active modes of transportation. Women prefer

to walk for active travel while men are more likely to utilize a bicycle. Individuals with higher levels of education walk significantly more Drug_discovery than those with lower levels of education. Employed individuals are more likely to drive alone than unemployed individuals. Other common determinants are the household characteristics, for example, income, household structure, and car and bicycle ownership [13, 15–17]. Households on higher incomes are more likely to own and use a car and families with children are more likely to use the car than one-person families. If households have cars, they would prefer to travel by cars. On the other hand, individuals with bicycle in their households have a higher propensity to participate in physically active pursuits. Travel attributes could also impact people’s mode choices [18].