Moreover, distance is an important factor for discrimination
between modes of transport linked with higher costs (public transport and car/motorcycle) and those with lower costs (walking and cycling). 3. Data Source and Preparation 3.1. Travel Diary Survey Data was collected from the activity-travel survey of Changxing County, China, in 2013. bcr Changxing is a county in the prefecture-level city of Zhejiang Province, with the area of 42km2 and the population of 250,000 residents. Taking a whole household as a unit, a random sampling and face-to-face interview were adopted for the survey on Wednesday, May 29, 2013. The investigators are required to select citizens randomly in different parts of the city in order to guarantee the quality of the sample. The sample involved a one-day (workday) activity-travel diary, which was designed to record all activities involving travel details such as purpose, mode, travel time, and origin destination of each trip, for all individuals above six years old in
the household. It also included sociodemographics of both household and individual. Finally, 4831 valid forms from 1809 households were collected. 3.2. Data Preparation The alternatives for travel mode choice used in this study are foot, bicycle (including tricycle), SOV (including moped and motorcycle), transit (including bus and company’s vehicle), and car (including private car and taxi). When implementing
rough sets analysis, returning purposes are excluded because mode choice of returning is largely associated with its former trip. This study is primarily concerned with the prediction of travel mode choice based on household and individual sociodemographics and travel attributes. These attributes and their corresponding categories are summarized in Table 1. Table 1 Attributes and their descriptions. 4. Rough Sets Theory Rough sets theory is a mathematical framework that deals with vague and potentially conflicting data and was first formulated in the early 1980s [6]. The theory has been refined and developed into a powerful set of knowledge discovery and data mining techniques [19, 20] and is still an active area of research, with researchers working on the extensions of the Batimastat theory [21, 22]. The theory has been implemented in a number of bespoke software such as ROSE [23], Rosetta [24], and RSES [25]. The theory belongs to the group of free-ranging algorithm and processes that aim to discover the knowledge contained within a dataset. In a dataset, it is possible to associate a particular outcome (e.g., travel mode choice) with a combination of values or levels held by other predictive attributes for a particular individual. When describing the process of deriving and applying the classification rules associated with rough sets, it is important to recognize that two stages are involved.