Zia Wadud

The impact of autonomous vehicles (AVs) on travel behaviour remains uncertain, largely due to two key factors: first, how individuals inherently perceive different privately owned and shared AV forms, and second, whether time is valued differently across these modes. The current study addresses both issues by developing a Bayesian panel mixed multinomial logit model based on a stated choice experiment conducted in the UK. The model empirically quantifies the inherent attraction and reservation effects associated with AVs, beyond those captured by service-level factors such as travel time and cost, and conceptualises them as the rest of convenience (ROC) value. ROC values suggest that AV modes are inherently less preferred than conventional alternatives, albeit with substantial heterogeneity among them. AV ride-hailing exhibited the lowest inconvenience barrier per trip (-£6.30), followed by AV minibuses (-£8.43), while private AVs (-£14.03) remained the least attractive AV option. Considerable disparity was also observed across socio-demographic groups and trip contexts, with a sizeable segment of potential early adopters (19-27%) already displaying positive perceptions towards AV services.At the same time, we estimate the value of time (VOT) across conventional and three AV modes (private AV, AV ride-hailing, and AV minibus). Results suggest that, compared with conventional cars, travel time is perceived as significantly more useful (30%) in private AVs, implying a lower disutility of travel time. However, this advantage diminishes as the mode becomes more shared, with AV ride-hailing exhibiting a VOT similar to that of manually driven cars, whereas AV minibuses exhibit a 47% higher VOT. The findings, therefore, indicate that automation alone does not eliminate the perceived inconvenience associated with shared travel. Taken together, the combined evidence on ROC and VOT provides a robust behavioural basis for assessing AV adoption and evaluating transport policies.

Vehicle electrification has become a major strategy for mitigating transport carbon emissions. Concerns have been raised about electric vehicle’s safety impacts due to their quieter driving and heavier weight compared to conventional internal combustion engine vehicles. This research utilizes Great Britain’s STATS19 road safety database to understand the pedestrian safety implications of electric vehicles. We show that the pedestrians are no more likely to collide with a fully (battery) electric vehicle compared to a conventional vehicle. In case of a collision, pedestrians are no more likely to be severely injured by an electric vehicle either. Hybrid electric vehicles have a higher pedestrian casualty rate – possibly related to their driving pattern – but the associated pedestrian injuries are less severe than those with internal combustion engine vehicles.

In this study, for the first time in the literature as far as we are aware, we model e-scooter use frequency and use purpose jointly, allowing for multiple use purposes. In doing so, we consider individual and household sociodemographics and psycho-social lifestyle considerations, as well as a residential location indicator. The analysis uses data collected through a survey of e-scooter users in Washington, D.C., U.S., administered electronically between September 2021 and December 2022. The results from our analysis indicate that gender, income earnings, motorized vehicle ownership in the household, a green lifestyle propensity, and a positive perception of e-scooters, in general, are the most important determinants of use frequency. Also, there are distinct demographic groupings between e-scooter use for hedonic (leisure and tourism-related) pursuits and utilitarian (shopping, work/appointments, and transit connections) pursuits. By understanding how changes in key influencing variables can affect use frequency and purpose, we provide richer insights for policy and initiatives involving frequency and integration, perceptions and marketing, sustainability, equity and accessibility, and mixed land-use practices.