A simultaneous model of household activity participation and trip chain generation

A trip generation model has been developed using a time-use perspective, in which trips are generated in conjunction with out-of-home activities, and time spent traveling is another component of overall time use. The model jo intly forecasts three sets of endogenous variables - (1) activity participa tion and (2) travel time (together making up total out-of-home time use), a nd (3) trip generation - as a function of household characteristics and acc essibility indices. It is;estimated with data from the Portland, Oregon 199 4 Activity and Travel Survey. Results show that the basic model, which has 10 endogenous time use and trip generation variables and 13 exogenous varia bles, fits well, and all postulated relationships are upheld. Test show tha t the basic model, which divides activities into work and nonwork, can be e xtended to a three-way breakdown of subsistence, discretionary and obligato ry activities. The model can also capture the effects of in-home work on tr ip chaining and activity participation. We use the model to explore the eff ects on time use and trip chaining of GIS-based and zone-based accessibilit y indices. (C) 2000 Elsevier Science Ltd. All rights reserved.