Value of Time and Elasticity of Portuguese Freeway Users: Insights from Analysis of Survey Data

Abstract

Value of time (VOT) is a crucial aspect of travel demand modeling. VOT impacts most mobility projects and the evaluations therein. It has been noted to be influenced by multiple factors, mainly related to individuals’ demographics and trips’ characteristics. This paper presents the results of a survey conducted among users of the Portuguese national freeway network, aiming to derive insights about their travel choice mechanism for testing mobility projects, in particular dynamic pricing strategies. Particular attention is dedicated to the value they attribute to travel time by analyzing willingness-to-pay for avoiding congestion and saving travel time. An elaborate questionnaire survey was distributed through online survey campaigns between March and June of 2021, eliciting 163 valid responses. Even after a stratification process, results revealed that VOT is generally lower than our original expectations; various statistical distributions were tested to fit the empirical data, the best performing ones were selected and the results were compared with a previous survey-based VOT study. We finally measured the elasticity of the freeway demand and of the whole demand for transportation, which confirmed the generally low willingness to pay for less congested travels.