Most of the studies on travel patterns in behavioral geography have been done assuming single purpose trips. Recently, however, some attempts to explain human spatial behavior pay attention to multipurpose trips from the viewpoint of comprehensive explanation of actual behavior. These studies emphasize the importance of the temporal dimension. Paying attention to this trend, this paper examines the patterns of daily travel behavior, focusing upon multipurpose trips, through considering the relationship between cyclic trip patterns (i. e. home-to-home circuit) and the daily trip patterns of individuals, and the influence of accessibility and travel-activity time on multipurpose trips.
The data used in this study are based on the personal trip survey conducted by the prefectural government in the city region of Hiroshima in 1978. The trip patterns are classified by the number of trips in each cycles, the sequence of activities, and the combination of cycles with that of trips per day, indicated by “B(a, b)”, where “a” refers to the number of cycles carried out per day and “b”refers to the number of trips carried out per day.
The results obtained are as follows:
(1) Multipurpose trips comprise 18.3 percent of all the cycles. The rate of multipurpose trips varies according to the characteristics of individuals due to the degree of obligation for activities they carry out.
(2) The four main trip patterns, B(1, 2), B(1, 3), B(1, 4), B(2, 4), comprise more than nine-tenths of all the trips by individuals (Fig. 2). Relating the trip patterns by individuals to those of cycles, the more trips are contained in a cycle or the greater the degree of obligation for activities is, the fewer patterns occur with more than one cycle per day (Table. 7).
(3) A positive correlation is detected between the rate of multipurpose trips and the accessibility from the destination of the first trip to other establishments. The relationship between the rate of multipurpose trips and the accessibility from the residence to other establishments, however, is more complicated. That is, as for the areas where the accessibilities are very high, the rate of mulpurpose trips decreases with the accessibility, although the rate has positive correlation with accessibility generally (Fig. 4).
(4) Based on the combination of activities, a hypothesis for the generation of multipurpose trips is proposed and partly supported (Table. 8). The hypothesis is as follows;
1) In cycles consisting of discretionary activities, travel time per stop in a multipurpose trip is shorter than that in single purpose trip, due to the principle of least effort.
2) In cycles combining obligatory activities with discretionary ones, the longer the time of obligatory stay and movement, the fewer multipurpose trips occur, since obligatory activities have an effect on discretionary ones as constraints.
3) The cycles consisting of business activities are highly influenced by the nature of occupation, so that the rate of multipurpose trips varies according to the occupation.
As for unemployed housewives and employed housewives, however, the travel time of the first trip in each cycle and average travel time per stop are respectively related to multipurpose trips.