Institute of Transportation, MOTC

Yen-Yen Cheng, 2009.01
Institute of Transportation Science, Tamkang University

　　The dynamic route choice behavior is of the most interest to study the individual driver’s route choices under the influence of the route guidance information where individual driver makes consecutive route switch decisions along the traveling route.This particular issue has been successfully modeled with various forms and extensions under the notion of the “Indifference Bands” applied with Probit model specifications in recent years. However, this particular issue may be further investigated as game-like decisions of two perspectives: the game between road users (among whom makes individual route choice in response to traffic information) as an entity versus traffic management authority (who would distribute traffic and route guidance information to achieve its goal); and the game among road users (individual decision versus predicted others’ actions in response to traffic information).

　　This study focuses on the game between road users in response to traffic management strategies by authority. The experiment context includes two decision dimensions: day-to-day pre-trip route choice and en-route decisions with a period of ten consecutive working weeks (50 days) under various designated scenarios (sequences). As such, a three stage comprehensive controlled experiment has been conducted where selected subjects were selected to participate in a series of laboratory simulation as commuting drivers while the researcher as acting traffic management authority.

　　The tasks of this study are in two folds: the first to examine the explicit game where evolution of the individual’s (player’s) consecutive decision and associated playoffs along with aggregate system performance will be recorded and tested including the decision to decision dynamics and their final (convergence) state. The second task is to further modeling the disaggregate road user’s dynamic decision with embedded game concept in the notion of jointed indifference bands (specified as Probit model structure) such that the game elements will be treated as implicit attributes.

　　The major findings of thesis are summarized in following:

1. The responses from pre-experiment survey confirmed the game-like interactions between traffic management authorities and experiment subjects in terms of general recognitions of intentions and actions of each part.
2. The network reaches approximate user equilibrium UE state after a period of time for providing guidance information based on either UE or SO strategies by the management. However, the result is close to theoretical values with mixed strategy.These results demonstrate that using guidance information as traffic control measures to reach system optimum is unlikely, since it is not as forceful as normal traffic controls. However, a mixed strategy seems more promising.
3. It also shows that while route guidance can be recognized as one of the control strategies by traffic control authorities, its effectiveness is quite different from other strategies in terms of enforcement. As such, bi-level problem formulation with Stackelberg game style accompanying general cases of treating upper level as system optimum for traffic control and lower lever as user equilibrium for route choice is not that promising for the context of this study.
4. Two indifference band models (for partial information and full information)were successfully specified and calibrated with good associated statistical criteria.