Travel Behavior Implications of Information and Communications Technology in Puget Sound Region Krishnan Viswanathan and Konstadinos G. Goulias Transportation Research Record 1752 ■ 157 Paper No. 01-2767 K. Viswanathan, Department of Civil and Environmental Engineering, 201 Trans- portation Research Building; and K. G. Goulias, Department of Civil and Environ- mental Engineering and Center for Intelligent Transportation Systems, 205 Transportation Research Building, Pennsylvania State University, University Park, PA 16802. The explosive growth of information and communications technology (ICT) has given rise to new paradigms in the manner in which business is conducted and in which people conduct their everyday affairs. This new dimension has the potential to affect travel behavior in direct and indirect ways and has possible policy implications for transportation planning. A multivariate multilevel analysis is presented using data from the Puget Sound region. ICT use effects on travel behavior are examined in terms of activity and travel time expenditures in a day. Model formulation in the study accounts for day-to-day variation, controls the close relationship between activity participation and travel, and incorporates the contextual influence of households on individual behavior by using observed and unobserved heterogeneity regression model components. The findings in this study indicate that Internet use at home and in the workplace is asso- ciated with a reduction in travel times. In contrast, mobile technology use is associated with significantly longer travel times. However, the high level of person-to-person variance of this effect shows that there may be groups of people using technology in radically different and most likely conflict- ing ways (e.g., one group uses mobile technology to consolidate trips and the other to reach activity opportunities that require longer travel times). In terms of activity participation, none of the technologies appears to be a significant contributor to the difference in behavior among technology users and nonusers. Since the beginning of the 1990s, there has been a surge in the use of computers and the Internet, providing opportunities for entrepreneurs to develop and commercialize information technology (IT) products and services. As a result, a plethora of technology market penetration predictions are found in traditional media and the Internet. For exam- ple, in a survey The Economist (1 ) predicts that the Internet could, in the next couple of years, capture up to 5 percent of the American retail market and by 2010 electronic shopping could account for 15 to 20 percent of retail sales. This new dimension of the economy has the possibility to affect travel behavior in direct and indirect ways. The burgeoning rate of growth of the Internet and the proliferation of powerful and inexpensive home computers have made it possible to have flexible working arrangements. This flexibility can potentially affect the traditional notions of how people travel and participate in activities as well as their motivations for those activities. In addition, the growth in mobile communications devices can also radically affect how people conduct their affairs. This growth of IT may have implications that should not be ignored when the travel impacts of these technologies are assessed. Also, the mediating role played by IT for other travel-related policies (e.g., the increase in those who work flexible hours, the decrease in the propensity to carpool) should not be ignored. In a comprehensive review, Golob (2) states that accessibility (to activity locations) can no longer be measured in terms of travel time, distance, or generalized travel costs alone. Access to IT makes it possible for people to change their activities and not leave the con- fines of their homes or workplaces. Although this might be a small change in one individual’s travel behavior, the overall effects across the larger population can be significant. Given the importance of these technologies and services and their considerable potential in influencing activity-travel behavior, it is necessary to have a better understanding of the role of information and communications tech- nology (ICT) in activity participation and travel. For that reason, an analysis is provided here of a database designed to understand travel behavior. A few key questions addressed are as follows: • Is there a relationship between personal computer use and travel activity behavior? • Do higher levels of technology and information (the Internet) use mean more or less activity and travel? • What is the intervening role of mobile communications tech- nologies? • Is there a widespread difference in the role of ICT use in activity and travel? A brief background is presented, followed by a multilevel multi- variate analysis of the Puget Sound Transportation Panel (PSTP) survey data from individuals regarding ICT use, travel, and activ- ity participation. Multilevel models are used to study these inter- actions at both the household and individual levels while controlling for the relationship between activity participation and travel and other contextual factors. BACKGROUND Activity-based approaches to travel demand analysis treat travel as demand derived from the need for activity participation. In this way travel is viewed in the broader context of activity scheduling in space and time (2). Within this theoretical framework, increased access to the Internet and related IT makes it possible for people to adjust their activity and travel in order to improve the quality of their lives. In addition, the advent of e-commerce and m-commerce (e.g., use of