The influence of panel effects and inertia on travel cost elasticities for car use and public transport

Abstract

Studies on the impact of changes in travel costs on car and public transport use are typically based on cross-sectional travel survey data or time series analysis and do not capture intrapersonal variation in travel patterns, which can result in biased cost elasticities. This paper examines the influence of panel effects and inertia in travel behaviour on travel cost sensitiveness, based on four waves of the Mobility Panel for the Netherlands (comprising around 90,000 trips). This paper analyses the monetary costs of travel. Panel effects reflect (within wave) intrapersonal variations in mode choice, based on three-day trip diary data available for each wave. The impact of intrapersonal variation on cost sensitiveness is shown by comparing mode choice models with panel effects (mixed logit mode choice models with error components) and without panel effects (multinomial logit models). Inertia represents variability in mode choice between waves, measured as the effect of mode choice decisions made in a previous wave on the decisions made in the current wave. Additionally, all mode choice models include socio-economic and spatial variables but also mode preferences and life events. The effect of inertia on travel cost elasticities is measured by estimating mixed logit mode choice models with and without inertia effects. The main conclusion is that the inclusion of intrapersonal effects tends to increase cost sensitiveness whereas the inclusion of inertia effects decreases travel cost sensitiveness for car and public transport modes. Car users are identified as inert travellers, whereas public transport users show a lower tendency to maintain their usual mode choice. This paper reveals the inertia effects over four waves of repeated respondent’s data repeated yearly.

Estimating Mode Choice Inertia and Price Elasticities after a Price Intervention – Evidence from Three Months of Almost Fare-Free Public Transport in Germany

“…The probability of choosing an alternative i in wave w is now defined as the person's sequence of choices, expressed as the joint probably product of the probabilities between waves evaluated at all values of the parameters (La Paix et al, 2022):…”

“…Yañez et al (2009) extended this work and analysed the effect of inertia and shock on people's travel mode choices when a disrupted modification of the transport system occurs. González et al (2017) and La Paix et al (2022) have shown that estimating price elasticities without considering the effect of inertia on people's mode choices may lead to severe consequences when evaluating transport policies.…”

“…Recently, La Paix et al (2022) used the Mobility Panel of the Netherlands to evaluate the cost sensitiveness and inertia effect in travel mode choice. In addition, Yang and Timmermans (2015) studied the co-variation between transport mode choice and travel duration regarding fuel price fluctuation using data collected through GPS devices.…”

A study on the impact of housing prices on residents' travel frequency and transportation resilience in 35 Chinese cities

“…It was found that a decrease in airfares significantly increased air traffic [ 40 ]. Research has revealed that people tend to be inertial in their transportation trips [ 51 , 52 ]. Paix et al investigated the effect of inertia on trip price sensitivity.…”

“…Paix et al investigated the effect of inertia on trip price sensitivity. According to approximately 90,000 car and public transport trips in the Netherlands, the effect of inertia of individual travel behavior on travel cost sensitivity can be observed [ 52 ].…”