“…The first form is exponential, presented in such studies as Evans [18], Yang and Huang [19], Lam and Zhou [20], Yang and Kin [21], and Bellei et al [22], Yao et al [23], Jørgensen et al [24], and Klier and Haase [25]. Works on the other form, the linear function, have been done by Chang and Schonfeld [26], Chien and Spasovic [27], Tsai et al [28], Savage [29], Li et al [30], Chen et al [11], and Kim and Schonfeld [31]. In these studies, two function forms have been proved to significantly reflect fluctuation of demand by changes in generalized costs of trips, though they are formulated in different expressions.…”