To examine the impact of travel time variability on travelers’ daily commute trips, stochastic bottleneck models with semi-endogenous random delay and endogenous random delay are proposed, respectively. In the model of semi-endogenous random delay, travel time variability is related to both the demand and supply sides. It describes the uncertainty of travel time as a random delay in relation to congestion. In this framework, a uniform toll is applied to all the travelers in the bottleneck model to reduce the total demand and the congestion-related random delay. This consideration of elastic demand and endogenous random delay under tolling produces distinctive departure profiles and system performances. We present new definitions and propositions according to the perspectives of...[ Read more ]

To examine the impact of travel time variability on travelers’ daily commute trips, stochastic bottleneck models with semi-endogenous random delay and endogenous random delay are proposed, respectively. In the model of semi-endogenous random delay, travel time variability is related to both the demand and supply sides. It describes the uncertainty of travel time as a random delay in relation to congestion. In this framework, a uniform toll is applied to all the travelers in the bottleneck model to reduce the total demand and the congestion-related random delay. This consideration of elastic demand and endogenous random delay under tolling produces distinctive departure profiles and system performances. We present new definitions and propositions according to the perspectives of both users and the system.

To further illustrate the impact of travel time variability, we introduce travel variation cost as an additional cost. The variation cost captures not only travel time variation but also variation in the scheduling cost. The equilibrium condition is affected by both the expected travel cost and the variation cost. When user equilibrium is achieved, all the travelers share the same generalized cost. Under this framework, we study the departure profiles under moderate and high capacity variability, respectively. When the capacity is highly variable, even the last traveler should depart early to avoid the high late penalty. Then different scenarios of capacity waste under the single-step tolling scheme are illustrated extensively.

To reduce the impact of travel time variability, travelers may take advantage of many information sources, such as radio or TV broadcasting, websites or real-time traffic information apps. Previous research has considered various kinds of information provided to travelers but has mostly assumed that travelers effortlessly incorporate all the provided information into their decisions. However, it seems unrealistic to assume that travelers make use of all the available information as that would require considerable effort that could easily outweigh the potential gains from improving the timing of trips. Recognizing this, the study connects the rational inattention model in the microeconomics to the travelers’ departure and route choices under travel time variability (TTV), where the traveler also chooses an information strategy. That is in contrast to the neoclassical model which takes the traveler’s information as given. Here, the traveler’s information strategy is endogenously chosen, taking the cost of information into account.