Abstract
Enabled by the steady growth of urbanization and rise in e-commerce activities, there is a boom in demand for parcel shipment in many cities. Moreover, with the increasing attention on sustainable freight transport, there is a recognised need for logistics service providers to meet this high demand while implementing eco-friendly and efficient solutions to reduce congestion, emissions, and environmental impacts within urban areas. To address these challenges, integration of freight and public transport is one such innovative solution.
The central objectives of this thesis are to analyze the concept and components of this integration and examine how it fulfills parcel deliveries, as well as evaluating its feasibility and sustainability. Within the framework of this integration, two distinct research pathways have been pursued: crowdshipping using public transport and freight on transit.
Conventionally, the carrier will deliver the parcels to the receivers’ addresses directly. While crowdshipping enlists members of the public to pick up and drop off parcels, ideally en route along their pre-committed journeys. Individuals, such as commuters using public transport, can be engaged to fulfil deliveries as "crowdshippers".
The primary focus of the initial crowdshipping using public transport problem aims to investigate the willingness of public transport users to work as crowdshippers in Singapore and the key factors that will impact their willingness. Comprehending the inclinations of public transport users towards crowdshipping and their preferences is pivotal for informing the practical implementation of crowdshipping services. An online survey targeting public transport users in Singapore was conducted to assess their willingness and various preferences, encompassing parcel characteristics (size, weight, delivery urgency), payment modes, parcel pickup and dropoff locations, trip-specific variables (delivery times, trip purpose, detour time, and original journey time. The findings reveal that a significant majority of respondents (79%) express a willingness to serve as crowdshippers. Moreover, the study identifies key benchmarks for parcel size and weight limits for crowdshipping services, optimal parcel pickup/dropoff locations, and informs the design of a practical parcel-crowdshipper matching and compensation scheme. Concerns raised by respondents during their involvement in crowdshipping should be taken into account in the future development and deployment of crowdshipper services.
The second segment of the crowdshipping using public transport problem aims to explore the potential impacts of crowdshipping using public transport in a dense city, employing Singapore as a case study. An online pre-survey was initially conducted to investigate the willingness of transit passengers to act as crowdshippers. A parcel allocation model was developed to match parcels with public bus journeys. In case there are not enough crowdshippers available, the remaining parcels will be delivered using the carrier’s delivery vans which is subject to a vehicle routing problem. A comparative analysis utilizing real-world data underscores that in densely urbanized areas with extensive transit networks, crowdshipping through public transport holds promise as a sustainable urban goods transportation method.
The third dimension of the crowdshipping using public transport problem concentrates on parcel priority for crowdshipping and introduces a comprehensive framework to organize the scheme. Firstly, outlier parcels are identified as being suitable for crowdshipping. Following, these outlying parcels are matched with crowdshippers who retrieve them from a designated set of parcel lockers. Furthermore, this study delves into the viability of crowdshipping through the analysis of real-world data. By comparing a carrier’s performance with and without crowdshipping against a base case, the results highlight the potential of crowdshipping to reduce the distance traveled by delivery vehicles and associated carbon emissions, signifying its suitability as a sustainable solution for urban logistics in densely populated cities.
In the fourth facet of the crowdshipping using public transport problem, it focuses on optimization of locker locations building upon the outlier parcels identified in the third work as suitable for crowdshipping. These parcels are matched with crowdshippers who collect them from selected lockers with limited storage capacities. Additionally, the study investigates the viability of crowdshipping using real-world parcel delivery and transit ridership data in Singapore. Comparative analysis of the carrier’s performance in crowdshipping scenarios and a base case without crowdshipping highlights savings in delivery vehicle kilometers traveled and associated air emissions. The exploration of crowdshipping scenarios based on passenger availability and willingness throughout the day underscores substantial benefits. In sum, crowdshipping via public transport holds significant promise as a sustainable urban logistics approach in densely populated cities.
The final study of this thesis moves on to the freight on transit. This work investigates the integration of passenger and freight transport, by leveraging public transport, specifically the urban rail network, for freight deliveries. Parcels are initially transported from a warehouse to hubs located at train stations by large vehicles, before being transferred by rail to satellite train stations. Subsequently, final deliveries to end destinations are carried out by smaller vehicles operating from the satellites. The research is centered on strategic decisions concerning the locations of hubs and satellites, as well as tactical planning encompassing routing and parcel assignments within the network. A three-echelon public transport-based freight transport system is proposed to address this challenge, including matching, routing, and location aspects. An iterative heuristic algorithm is developed to pinpoint the optimal satellite locations, resulting in a significant reduction in vehicle kilometers traveled, as evidenced by real-world data analysis in Singapore.
Collectively, this thesis emphasizes the potential of integrating freight with public transport, encompassing crowdshipping and freight transit, as sustainable solutions to address urban logistics challenges in densely populated cities.