Structural Analysis on Activity-travel Patterns, Travel Demand, Socio-demographics, and Urban Form: Evidence from Cleveland Metropolitan Area

摘要

Research on travel behavior continues to be one of the most prominent areas in the transportation area. Planners and policymakers try to understand and manage travel behavior. Making and implementation of travel demand management (TDM) policies greatly rely on the understanding of the determinants of activity-travel patterns and travel demand. Among the activity-travel patterns, trip chaining and joint travel have received much research interest. Trip chaining is typically viewed as a home-based tour that connects multiple out-of-home activities. Joint travel is commonly defined as traveling with others. Travel demand is generally measured by trip generation and travel distances. Investigating different aspects of travel behavior helps us better understand the links between activity participation and mobility, and improves the evaluation of the transportation infrastructure investments and policies such as high occupancy vehicle (HOV) lanes and vehicle miles traveled (VMT) reduction programs.;Several studies have regarded trip chaining, joint travel, trip generation, and travel distances as different dimensions of travel behavior to be examined in terms of various socio-demographics and urban form factors. However, limited work has been done to use activity-travel patterns as mediating variables and analyze how trip chaining and joint travel shape the resulting travel demand. Furthermore, relationships between travel behavior and urban form factors at out-of-home activity locations remain unclear. Based on the 2012 travel survey data from the Cleveland Metropolitan Area, this study first investigates the relationships among trip chaining, joint travel, home-based tour generation, and travel distances at three different levels: tour, individual, and household levels. Second, the influences of socio-demographics and urban form factors at tour origins and destinations on travel behavior are examined simultaneously. Lastly, while using trip chaining and joint travel as mediating variables, this study estimates the mediating effects of socio-demographics and urban form via activity-travel patterns on travel demand. The Structural Equation Modelling (SEM) approach is applied.;The study reveals the existence of significant relationships between activity-travel patterns and travel demand. Trip chaining is negatively associated with joint travel. While it increases travel distances, this effects gets weakened through its indirect effect via decreased tour generation. Joint travel appears to increase tour generation but decrease the travel distances. Most socio-demographics have significant effects with expected signs on travel behavior. The analysis suggests that urban form factors at tour origins and destinations play important roles on the resulting travel demand. Some urban form factors may not have direct effects on travel demand but have significant indirect effects on tour generation or travel distances through activity-travel patterns. This research presents how activity-travel patterns shape travel demand and concludes that trip chaining and joint travel should be taken into consideration while analyzing travel demand. The findings on socio-demographics and urban form factors can be used as inputs to improve the future evaluation of transportation projects and help planners integrate land-use strategies as tools to change people's travel behavior. This will further mitigate the negative externalities associated with our travel patterns.