McFadden Aurora Kinase cancer innovatively introduced the “utility theory” of economics into transportation and proposed a new logit mode called the “random utility model” [21, 22]. Domencich presented a discrete choice
model based on “maximum utility theory” and then further divided the disaggregate model into the logit model family and the probit model family, based on which a theoretical system of the disaggregate model was gradually formed . Ben-Akiva, Lerman, and Vovsha further introduced the theory into traffic demand forecasting, conducting deep research into the transportation division problem and pushing the logit model into the practical application stage [24, 25]. By analyzing individuals’ unobserved and observed preferences and characteristics, Bhat used the multinomial logit model (MNL) to describe the personal preference for transportation and analyzed individuals’ travel mode choice behavior under different service levels . In economics, it is assumed that consumer preferences
can be represented by a continuous utility function, which can be mathematically proved. According to random utility theory, travelers will choose the travel mode at their perceived maximum utility in a specific situation. According to random utility theory, the utility function U consists of nonrandom and random parts as follows: Uin=Vin+εin, (1) where Uin is the utility function of the alternative travel mode i(i = 1,2,…, J) of traveler n(n = 1,2,…, N); Vin is the nonrandom part of the utility function; and εin is the random part of the utility function, which are submitted to Gumbel distribution and independent from each other. Traveler n would choose i if and only if Uin>Ujn, i≠j, i,j∈An, (2) where An is the set of all possible travel mode choices of traveler
n. According to maximum utility theory, the probability that traveler n will choose travel mode i is denoted as Pin as follows: Pin=ProbUin>Ujn;i≠j, i,j∈An=ProbVin+εin>Vjn+εjn;i≠j, i,j∈An, (3) where 0 ≤ Pin ≤ 1, ∑i∈AnPin = 1. 4. Data and Application 4.1. Sample, Predictor, and Data Processing This paper chooses Tangshan as the sample city. Tangshan is a medium-sized city located in North China, the economic development level, city size, and traffic conditions of which are in the intermediate state. There is no subway in Tangshan, and motorcycles have been banned from the urban district. The set of alternative travel modes available for residents is denoted as GSK-3 A: A = i∣i = 1, walking; i = 2, bicycle; i = 3, electricbicycle; i = 4, bus;i = 5, taxi; i = 6, privatecar. Field investigation by questionnaire survey is conducted to find the factors affecting the travel mode choice. Thirteen possible factors of personal characteristics, family-owned private travel tool characteristics, and travel characteristics are the assumed variables (k is the number of variables; k = 1,2,…, K, K is the total number of variables), which are presented in Table 1.