Transportation Research Record 1752 ■ 69 Paper No. 01-2712 The interactions between the heads of a household with regard to their out-of-home activities and travel behavior in Upper Austria are investi- gated. To answer the research questions, a structural equation model is developed. The data used in the modeling process are from an extensive travel diary of over 100,000 households in Upper Austria combined with extensive data on land use and local economic activities. The main result of the model is that sex-specific division of labor in nuclear families is still common. If women are working, the number of their maintenance trips is reduced, but this reduction is not compensated for by men. Normally, female employment is connected with a decrease in the number of other female activities and an increase in car ownership and traveled dis- tances. In addition, the model shows that out-of-home activities often are carried out together. The number of reachable infrastructure facilities is the most important spatial variable, whereby good access promotes the reduction of car-ownership and traveled distances. The nuclear family with a sex-specific division of labor was the dom- inant family type for several decades. This family type was character- ized by a father working outside the home and a mother staying at home doing the housework and bringing up their children. The impor- tance of this family type has decreased in the last four decades in Aus- tria, as elsewhere. On the one hand other household types have become more prominent, for example, singles, one-parent families, childless couples, unmarried couples, or those with shared living arrangements (1, 2). The single household is the most common of these household types. On the other hand, changes within the nuclear family have taken place, especially with regard to the role of wives (3, pp. 417– 425; 4 ). Although the majority of married women stayed at home in the 1950s and 1960s, today most women, even mothers, are working, at least part time. Women are no longer only responsible for the house- hold; they also take part in the working world. The consequence of this development is often a double or a triple burden for mothers (5–7 ). In contrast to the woman’s life, the life of men has hardly changed. They are still mainly working and do not participate in the domestic sphere (8–10). The general assumption is that the sex-specific division of labor is still dominant in spite of the increasing share of working women. Few studies have tested empirically how families really manage everyday life and how these arrangements affect travel behavior. In this paper an attempt is undertaken to analyze the interrelationships between the heads of a household with regard to out-of-home activ- ities and travel behavior. The analysis is limited to parents because the question of the division of labor becomes decisive if children live in a household. In addition, spatial differences between the home locations are taken into consideration. REVIEW The unit of analysis in this paper is the individual within the house- hold, interacting with the social and spatial environment, as well as the household as a whole. Understandings developed from activity- based travel demand models form the basis of the analysis. The activity-based approach to the analysis of travel behavior and travel demand originated in the United Kingdom, the United States, and Germany in the 1970s to overcome the limitations of the stan- dard four-stage approaches. The starting point of the approach was the switch of focus from aggregate trip making to individual activ- ity participation and the identification of travel as a derived demand. The work was stimulated by developments in geography by Häger- strand (11) and in urban planning by Chapin (12). Both had analyzed the activity patterns of individuals and groups of individuals. Although the unit of analysis was the same, the two approaches had different basic assumptions. Chapin saw travel primarily as a result of individ- ual preferences and unconstrained choices, whereas Hägerstrand saw it as the outcome of fulfilling a complex set of constraints (capability constraints, coupling constraints, and authority constraints). The activ- ity approach recognizes both and analyzes travel and activity behavior as “choice in the context of constraints” (13, p. 266). It is this fuller understanding that allows the activity-based approach to offer more comprehensive and insightful analyses of travel behavior. The initial studies of the activity-based approach showed that travel behavior is strongly influenced by sociodemographic characteristics (14, 15). This finding was investigated in greater detail during the 1980s and 1990s, with a focus on, for example, the life cycle, per- son characteristics, the impacts of income and available time, gen- der differences, and household structure and interactions (16, 17 ). In the last kind of model, the focus was on the household heads and their interactions (18; 19, pp. 365–398). UPPER AUSTRIA Upper Austria is one of the nine Austrian provinces located to the west of Vienna, to the east of Munich, and to the south of Prague. It has a size of 12 000 km 2 and about 1.3 million inhabitants. At a gen- eral level Upper Austria can be divided into three parts: • Böhmisches Massiv in the north, • Alpenvorland in the middle, and • Alps in the south. The northern part of Upper Austria is disadvantaged in several ways. This area is well suited neither for agriculture nor for tourism. In addition the border to the Czech Republic was closed for the five decades of the Cold War. As a result the possibilities for industrial Within-Household Allocation of Travel Case of Upper Austria A. Simma and K. W. Axhausen Institute of Transportation, Traffic, Highway and Railway Engineering (IVT), Swiss Federal Institute of Technology (ETHZ), CH-8093 Zürich, Switzerland.