The policy interventions aimed towards sustainable transportation directly or indirectly aim to reduce vehicle miles traveled (VMT). Self-reported VMTs in travel surveys are traditionally used 1) to quantify the impact of policy on travel behavior and 2) to understand the factors affecting VMT. However, VMTs collected in travel surveys are subject to large measurement errors for several reasons, including participants’ memory decay, carelessness, and rounding/approximate measurement of distances. Alternative methods, like GPS-enhanced and mobile app-based surveys, can provide more accurate VMT data. However, they are intrusive, expensive, hard to scale, and suffer from lower response rates. Therefore, the samples collected from these technology-enhanced methods may prove problematic in terms of generalization and representativeness of the population.
This project will focus on VMT measurement through two main tasks: 1) a state-of-the-art literature review of the methods to collect information about VMT, to date, in transportation studies, with an assessment of their pros and cons, 2) the development of a framework to collect pictures of odometer readings from participants via instant messaging services APIs and the testing of this approach through a pilot deployment and evaluating under what circumstances (if any) this method could provide benefits that overcome its limitations, compared to other existing approaches. Through these tasks, the study will provide much-needed guidelines and information for planners, policymakers, and researchers and allow testing a methodology that is expected to be relatively cost-effective, less intrusive than other methods, and has the potential to provide accurate VMT.