Maria Kamargianni

Generation Y’s Travel Behavior and Perceptions of Walkability Constraints

The aim of this study was to investigate the interrelationship between urban environment and walking to school and how teenagers’ perceptions of walkability (i.e., how friendly an area is to walking) constraints affected their mode choice. An advanced hybrid mode choice model was developed in which the utilities of the alternative modes depended on the mode characteristics, teenagers’ socioeconomic characteristics, weather conditions, and built environment characteristics, as well as a latent variable referring to walking constraints. The indicators of the latent variable included perceptions regarding the existence of stray animals, poor lighting, narrow sidewalks, parked cars that obscure visibility, unsignalized intersections, and probability of attack and safety en route. A questionnaire survey that took place at high schools of three distinct geographic areas in Greece (an urban area, a rural area, and an insular area) during 2011–2012 was the basis for a case study; 1,988 high school students aged 12 and 18 years old participated in the survey. Adolescents in rural areas walked a greater distance than did urban and insular adolescents. Model estimation results showed that teenagers from each geographical area were affected in different ways by weather conditions and they also perceived the built environment in different ways; this perception indicates how significant the sense of place is. The incorporation of the latent variable enhanced the explanatory power of the model, and the results of the study provide insights on policies that may help Generation Y to keep walking.

Air Pollution and Seasonality Effects on Mode Choice in China

A modal shift from motorized to nonmotorized vehicles is imperative to reduce air pollution in developing countries. Nevertheless, whether better air quality will improve the willingness to use nonmotorized transport remains unclear. If such a reciprocal effect could be identified, a sort of virtuous circle could be created (i.e., better air quality could result in higher nonmotorized transport demand, which in turn could further reduce air pollution). Developing countries may, therefore, be more incentivized to work on air pollution reduction from other sources to exploit the extra gains in urban transport. This study investigated the impact of air pollution on mode choices and whether nonmotorized transport was preferred when air quality was better. Revealed preference data about the mode choice behavior of the same individuals was collected during two seasons (summer and winter) with different air pollution levels. Two discrete mode choice models were developed (one for each season) to quantify and compare the impacts of different air pollution levels on mode choices. Trip and socioeconomic characteristics also were included in the model to identify changes in their impacts across seasons. Taiyuan, a Chinese city that operates a successful bikesharing scheme, was selected for a case study. The study results showed that air quality improvement had a significant, positive impact on nonmotorized transport use, which suggested that improvements in air quality and promotion of nonmotorized transport must be undertaken simultaneously because of their interdependence. The results of the study could act as a harbinger to policy makers and encourage them to design measures and policies that lead to sustainable travel behavior.

A stated preference experiments for mobility-as-a-service plans

As the Mobility as a Service (MaaS) concept gains wider acceptance, there is increased demand for understanding more about MaaS subscription plans. This paper presents the design of a stated preference (SP) experiment that captures the complex decision making process of purchasing MaaS products. It uses a prompted recall smartphone based travel survey tool that is expanded by a SP experiment regarding MaaS plan choices. Respondents are presented with repeated choices between four hypothetical MaaS plans out of which three are fixed plans and one is a menu option. This approach allows for testing peoples preferences and willingness to pay for flexibility. The attributes of the plans include transport modes and amounts, mode specific features (e.g. 10-minute taxi guarantee), transferability (meaning how much of left over mode-attributes can be transferred to the next month), special prizes (e.g. a free dinner for two) and the price of the plan.

Car Travel Demand: Spillovers and Asymmetric Price Effects in a Spatial Setting

A novel analysis framework for the spatial aspects of car travel, measured by vehicle miles traveled (VMT), is introduced in this paper. The specification of a dynamic spatial Durbin model enables the analysis of VMT spatial spillovers and diffusion between neighboring areas in the short and long run. The framework is further developed to capture and introduce to a spatial setting potential asymmetry and hysteresis that can reflect reference dependence and habits. A panel data set is compiled at the subregional level, based on official car mileage recordings in England and Wales. In addition to the inelastic long-run responses of VMT to fuel price (−0.124) and income (0.116) changes, the results illustrate asymmetries and hysteresis in price elasticities with a significant spatial component. The impact magnitude on VMT from a number of factors, such as alternative fuel use, fuel deserts in rural areas, and road network and car fleet characteristics, is also estimated. The results are consistent with the c...