The Variability of Travel Time, Users' Uncertainty, and Trip Information: A New Approach for the Cost-Benefit Analysis

Abstract : Travel time saving plays an important role in the socio-economic studies of the profitability of transport projects. The present paper includes four main parts. In the first section, we describe how the decisions of travelers are influenced by the variability of travel time. The statistical analysis of the recorded travel time on a motorway in Île-de-France is developed to quantify the variability of travel time and to measure its magnitude. The second section is devoted to developing the methodological framework to capture the safety margin considered by travelers in their trip making behaviors. A model is formulated to reflect the behavior of the traveler before making a trip. This model highlights the effect of each travel component, the mean of the travel time, the level of variability, and the safety margin taken by the traveler before traveling. The third section extracts the optimal safety margin that minimizes the cost of the total time allocated to travel. Finally, the last section of this paper is devoted to some algebraic manipulation in order to characterize the features of the output if the variability of travel time in the economic evaluation of transport projects is incorporated. An expression is also provided for the gain brought by operators when they reduce the variability of travel time or they reduce the uncertainty felt by travelers through providing information to them.