Towards Sustainable Multimodal Mobility Futures: Exploring bike-transit synergy in mid-sized, car-oriented urban areas

Abstract

This article-based PhD thesis aims to explore the potential of the synergy between bicycles and public transport to offer a sustainable and attractive alternative to car use for commute trips. It focuses on sprawled, midsized, and car-oriented urban areas where a substantial deployment of electric cars (EVs) has been achieved. More specifically, this study first discusses the contribution of EVs to sustainable urban mobility and sets the contextual background of this research by examining the impact of their incentivisation and wider deployment in the field of travel behaviour research, using the region of Nord-Jæren in Norway as a case study. Then, motivated by this discussion and from the existing challenges of promoting alternative travel options, such as bicycles and public transport, it looks into the potential of their synergy. Therefore, the potential contribution of bicycles to improving the job accessibility levels of the existing public transport system in Nord-Jæren is estimated, assuming an efficient integration. The contribution of this integration in providing more fair access to employment opportunities and its competitiveness to the car are also discussed. This study also explores how the perceived quality of this integration influences the choice to combine bicycles with public transport. Finally, it explores the preferences of commuters for this synergy for the case of Nord-Jæren and discusses the factors that influence different groups of commuters into choosing this travel option. To achieve this, a mixed-method approach has been followed, consisting of both system-centric and user-centric methods. More specifically, five types of analysis are used in the thesis, which are: – Systematic literature review (Article I) – Existing behaviour analysis using revealed preference data (Articles II and III) – Spatial analysis of accessibility (Article IV) – Analysis of the effects of the quality of integration using revealed preference data (Article V) – Explore preferences using choice analysis of stated preference data (Article VI)

Article I presents the results of the systematic literature review and provides an overview of the factors that have been found to influence the uptake of bike-transit combination. It also discusses existing knowledge on the expected effects of bike-transit combination on existing public transport systems and car use levels. Lastly, it presents the current gap in knowledge regarding its alleged potential to provide an alternative to the car. Articles II and III use revealed preference data to explore the influence of high deployment of EVs on existing knowledge and axioms on travel behaviour research. More specifically, Article II examines whether promoting EVs undermines parallel efforts to reduce car use. It explores the concept of moral licensing that allows travellers to feel good about their environmental contribution while maintaining their existing caroriented lifestyle. The results confirm that pro-environmental beliefs have a “spillover effect” on EV use due to existing positive car attitudes. The relative convenience of the car over alternative options has been found to be the most important mitigating factor in the influence of environmental beliefs on behaviour. Article III presents the existing district groups of commuters in Nord-Jæren and discusses their differences with existing literature. This study brings new insights on traveller segmentation based on travel behaviour in a high EV context, as it identified two car-dedicated groups of travellers, with the sole difference being whether they use an EV or not. This study suggests that in such contexts, higher environmental awareness should not necessarily be associated with lower car use or higher use of alternative options, and neither should this phenomenon be considered a dissonance. Article IV discusses the differences in potential job accessibility levels of Nord-Jæren provided by four travel options: car, public transport, bicycle, and bike-transit synergy. The results indicate that the benefits of bike-transit synergy are more pronounced in peri-urban areas, where the integration significantly enhances accessibility in the least accessible areas. It also provides a fairer distribution of job accessibility in the region compared to the car. However, the findings suggest that while bike-transit synergy is beneficial, it alone cannot resolve gaps with existing job accessibility levels provided by the car, reinforcing the need for an integrated transport and land use planning approach. The findings also highlight the need for considering alternative travel options as well as different equity definitions for a more coherent transport equity analysis. Article V delves into the factors that cause transfer inconvenience during trips combining bicycles and public transport and measures their effect on the decision to do so. The results of the analysis suggest that practical elements, like physical infrastructure, play a vital role in shaping transfer inconvenience. They also showed that transfer inconvenience plays a substantial role in the choice to combine bicycles and public transport as it can alone explain up to 10% of its variance. However, solely improving integration might not cause a sufficient nudge towards this travel option due to other factors influencing its uptake. Article VI explores the potential of bike-transit combination in Nord-Jæren and provides insights into the factors influencing mode choice among different commuter groups. To achieve this goal, a stated preference experiment observing mode choice under hypothetical scenarios was conducted among commuters in Nord-Jæren. In this study, two groups of commuters have been identified that are more likely to adopt the combined use of bicycles and public transport. These were named Green Travelers and Flexible Travellers and constitute 60% of the sample. Flexible Travellers (42.2% of the sample) can also play a pivotal role in the transition to more sustainable urban mobility in Nord-Jæren, due to their willingness to shift between modes. For both groups, the relative attractiveness of alternatives in terms of travel time and cost can play an important role in the uptake of bike-transit synergy. Moreover, two additional groups of commuters have been observed, called Dedicated Motorists and Aspiring Cyclists, which both show a preference for unimodal options. The first has a clear preference for the car, while the second shows a clear preference for the bicycle. However, both present an unrealised potential, since enforcing car traffic restrictions such as road tolls and car parking charges would nudge them towards more sustainable alternatives reducing their car use levels even further.