Although an origin destination (OD) survey is devoted to describe in detail the travel pattern in a particular period, the information collected allows recovering, with some level of aggregation, a description of time use of the individuals observed. This allows the possibility to calibrate the time use mode choice model system proposed by Jara-Diaz and Guerra (2003) with a very rich and trustable database. This possibility is explored for the Santiago 2001 OD survey (Ortzar et al, 2003) that has more than 12,000 households sampled randomly from the population of Santiago, each observed during a whole day. As a first stage of this process, we analyze the available information and identify the possible ways to build adequate descriptions of the individuals time assignment to different activities. The sociodemographic characteristics of the sample, which could be used as segmentation variables and to link observations, was also observed. The objective of this work is to obtain from the OD survey, a database similar to one obtained specifically with the purpose of calibrating the time use mode choice model system, which is much smaller in size. The information required to calibrate the time use mode choice model system, and how it can be obtained from the Santiago 2001 OD survey is identified. From this information, we obtain the time allocation to different activities of a representative sample of the inhabitants of Santiago (the OD sample), and analyze the individuals characteristics that influence these time allocations. There are two basic ways to describe the time assignment of a group of individuals: trough the average time assignment and through the activity pattern, that represents the proportion of individuals who are conducting each particular activity at any instant through a period of time, for example a day. Because the OD survey is a travel survey and not a time use survey, the activities can only be obtained through trip purposes, and the degree of aggregation is constrained to the trip purposes included in the OD survey. The detail of what happens inside each of these aggregate activities is not known. The activities that can be deduced from the Santiago OD survey are: stay at home, work (out of home), study (out of home), recreation (out of home), shopping and errands, travel, other activity out of home. As each individual was observed only during one day, the activity patterns of the different days of the week come from different individuals. Although comparisons among days can be made, it would be interesting to build weekly observations through linking observations of very similar individual observed in different days of the week. The analysis is centred on the possibility of aggregating information and generating databases rich in variance, that allow to calibrate the time use mode choice model system, already applied to smaller databases. If we prove it feasible to obtain all the information required from such a large and rich database, we will then count with a very powerful approach to the better understanding of individuals behaviour. For the covering abstract see ITRD E137145.
Abstract