| 1. |
- Chen, Haoye, et al.
(author)
-
Pick-Up and Delivery Problem for Sequentially Consolidated Urban Transportation with Mixed and Multi-Pupropse Vehicle Fleet
- 2022
-
In: Journal of Advanced Transportation. - : Hindawi Limited. - 0197-6729 .- 2042-3195. ; 2022
-
Journal article (peer-reviewed)abstract
- Different urban transportation flows (e.g., passenger journeys, freight distribution, and waste management) are conventionally separately handled by corresponding single-purpose vehicles (SVs). The multi-purpose vehicle (MV) is a novel vehicle concept that can enable the sequential sharing of different transportation flows by changing the so-called modules, thus theoretically improving the efficiency of urban transportation through the utilization of higher vehicles. In this study, a variant of the pick-up and delivery problem with time windows is established to describe the sequential sharing problem considering both MVs and SVs with features of multiple depots, partial recharging strategies, and fleet sizing. MVs can change their load modules to carry all item types that can also be carried by SVs. To solve the routing problem, an adaptive large neighborhood search (ALNS) algorithm is developed with new problem-specific heuristics. The proposed ALNS is tested on 15 small-size cases and evaluated using a commercial MIP solver. Results show that the proposed algorithm is time-efficient and able to generate robust and high-quality solutions. We investigate the performance of the ALNS algorithm by analyzing convergence and selection probabilities of the heuristic solution that destroy and repair operators. On 15 large-size instances, we compare results for pure SV, pure MV, and mixed fleets, showing that the introduction of MVs can allow smaller fleet sizes while approximately keeping the same total travel distance as for pure SVs.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Hatzenbühler, Jonas, et al.
(author)
-
Determining the optimal allocation of automated buses on a public transport network
- 2019
-
Conference paper (other academic/artistic)abstract
- Background: This research is driven by the general need for affordable, frequent and convenient Public Transport (PT) solutions. Over the last years the advances in the sector of autonomous systems have triggered studies on their effect on PT. AB lower the operational costs due to the removal of labor costs, which in developed countries account for more than half of the overall operational costs. These lower operational costs are expected to lead to higher service frequencies. The introduction of more diverse vehicle sizes is then possible and economical which will allow the operators to target the user demand better than with a fixed sized vehicle fleet. In this we analyse the use of AB systems in existing PT networks by:- define an AV specific objective function- integrate AV systems in a mesoscopic simulation framework- extract KPIs for the economic deployment of AB systems This study aims at answering the following research questions:- How can AB systems be used to improve passenger and operator costs on existing lines?- What are the implications of the cost trade off in terms of the defined KPI?- On which lines is the deployment of AB systems most interesting in terms of social welfare?Methods: The implementation of the framework adopts a simulation based optimization approach. The multi-agent simulation software (BusMezzo) uses the networks routes and the decision variables as input values. Subsequently the simulation is executed, and the filtered results will be handed to the Genetic Algorithm optimization. The objective function minimizes the overall cost which is the sum of operator costs (capital costs & operation cost) and user cost (travel time, waiting time, ticket cost,..). This loop is executed until convergence. The decision variables for the optimization module are the vehicle capacity, the frequency per route and the vehicle type. For validation of the optimization approach described above a brute force analysis is done on the synthetic Network provided by Spiess & Florian. In the brute force analysis the entire solution space for the network is displayed and can be analyzed. This allows for deeper understanding of the underlying processes and validates the optimization results. With the knowledge of this approach the optimization parameters are configured.Results: The proposed model was applied to a on-going pilot case study in the area of Kista in Stockholm. The proposed model is generally applicability for larger scale problems. Possible applications of the proposed methodology are:- tool for identifying the most promising areas for introducing AB- measurement for the economic impact of AB Systems on PT- the design of the network for a mixed operationPotential extensions of the model include the fleet composition and fleet size per line of special AB zones in high user demand areas.The main results and conclusions are:- Frequency and Capacity have comparable impact on total cost- Introducing Autonomous Vehicle on high demand lines is beneficial- There are "sweet spots" for operating for operating vehicle mixes- some configurations are only profitably operable with autonomous vehicle
|
|
| 5. |
- Hatzenbühler, Jonas, et al.
(author)
-
Fixed-line network design in light of autonomous buses
-
In: Transportation. - 0049-4488 .- 1572-9435.
-
Journal article (peer-reviewed)abstract
- The maturing of autonomous driving technology in recent years has led to several pilot projects and the initial integration of autonomous pods and buses into the public transport (PT) system. An upcoming field of interest is the induced demand level and changes in network design for public transport system operating autonomous buses. In this work a multi-objective optimization-based multi-agent simulation framework is developed to study potential changes in the network design and frequency settings when autonomous vehicles (AV) systems are deployed on fixed-route networks in addition to existing PT systems. During the optimization process multiple deployment scenarios (network configurations and service frequency) are evaluated and optimized concerning the operator cost, user cost and infrastructure preparation costs of the system. User-focused network design and operator-focused network design are studied for a real-world network in Sweden. The results provide insights into the network design and level of service implications brought about by the deployment of autonomous bus (AB) when those are integrated in route-based PT systems.
|
|
| 6. |
- Hatzenbühler, Jonas, et al.
(author)
-
Modular Vehicle Routing for Combined Passenger and Freight Transport
-
Journal article (peer-reviewed)abstract
- The continuous increase in urban deliveries and the ongoing urbanization of large cities require the development of efficient and sustainable transportation solutions. This study investigates the impact of modular vehicle concepts and the consolidation of different demand types in the route planning on the efficiency of the urban freight and passenger transportation system. Modularity is achieved by connecting multiple vehicles together to form a platoon. The consolidation of different demand types is realized by simultaneously consider passenger and freight demand in the optimization algorithm. The considered vehicles are specific for each demand type by can be connected freely, hence it is possible to transport different demand types in the same platoon. The cost terms in the problem formulation are comprised of travel time costs, travel distance costs, fleet size costs, and cost considering unserved requests. The modular vehicle operations are modeled in a novel pickup and delivery problem which is solved using CPLEX and Adaptive Large Neighborhood Search (ALNS). In an extensive scenario study, the potentials of the new modular vehicle type are explored for different spatial and temporal demand distributions. A parameter study on vehicle capacity, vehicle range and cost saving assumptions is performed to study their influence on the efficiency. The experiments carried out indicate a general cost savings of 48% due to modularity and an additional 9% due to consolidation. The reduction mainly stems from reduced operating costs and reduced trip duration, while the same number of requests can be served in all cases. Empty vehicle kilometers are reduced by more than 60% by consolidation and modularity. The proposed model and optimization framework can be used by companies and policy makers to identify required fleet sizes, optimal vehicle routes and cost savings due to different types of operation and vehicle technology.
|
|
| 7. |
- Hatzenbühler, Jonas, et al.
(author)
-
Modular vehicle routing for combined passenger and freight transport
- 2023
-
In: Transportation Research Part A. - : Elsevier BV. - 0965-8564 .- 1879-2375. ; 173, s. 103688-103688
-
Journal article (peer-reviewed)abstract
- This study investigates the potential of modular vehicle concepts and consolidation to increasethe efficiency of urban freight and passenger transport. Modularity is achieved by connectingmultiple vehicles together to form a platoon. Consolidation is realized by integrating passengerand freight demand in the routing problem. Vehicles are specific for each demand type but canbe connected freely, allowing the transport of multiple demand types in the same platoon. Therouting problem formulation considers travel time costs, travel distance costs, fleet size costs,and unserved requests costs. The operations are modeled in a novel modular multi-purposepickup and delivery problem (MMP-PDP) which is solved using CPLEX and Adaptive LargeNeighborhood Search (ALNS). In an extensive scenario study, the potential of the modularvehicle type is explored for different spatial and temporal demand distributions. A parameterstudy on vehicle capacity, vehicle range and platoon cost saving is performed to assess theirinfluence on efficiency. The experiments indicate a cost saving of 48% due to modularity and anadditional 9% due to consolidation. The reduction mainly stems from reduced operating costsand reduced trip duration, while the same number of requests can be served in all cases. Emptyvehicle kilometers are reduced by more than 60% by consolidation and modularity. A large-scalecase study in Stockholm highlights the practical applicability of the modular transport system.The proposed model and optimization framework can be used by companies and policy makersto identify required fleet sizes, optimal vehicle routes and cost savings due to different typesof operation and vehicle technology
|
|
| 8. |
- Hatzenbühler, Jonas, et al.
(author)
-
Multi-purpose Pickup and Delivery Problem for Combined Passenger and Freight Transport
-
In: Transportation Research Part E. - 1366-5545 .- 1878-5794.
-
Journal article (peer-reviewed)abstract
- Recent developments in modular transport vehicles allow deploying multi-purpose vehicles which can alternately transport different kinds of flows. In this study, we propose a novel variant of the pickup and delivery problem, the multi-purpose pickup and delivery problem, where multi-purpose vehicles are assigned to serve a multi-commodity flow. We solve a series of use case scenarios using an exact optimization algorithm and an adaptive large neighborhood search algorithm. We compare the performance of a multi-purpose vehicle fleet to a mixed single-use vehicle fleet. Our findings suggest that total costs can be reduced by an average of 13% when multi-purpose vehicles are deployed, while at the same time reducing the total vehicle trip duration and total distance travelled by an average of 33% and 16%, respectively. The size of the fleet can be reduced by an average of 35%. The results can be used by practitioners and policymakers to decide on whether the combination of passenger and freight demand flows with multi-purpose vehicles in a given system will yield benefits compared to existing fleet configurations.
|
|
| 9. |
- Hatzenbühler, Jonas, et al.
(author)
-
Multi-purpose pickup and delivery problem for combined passenger and freight transport
- 2024
-
In: Transportation. - : Springer Nature. - 0049-4488 .- 1572-9435.
-
Journal article (peer-reviewed)abstract
- Recent advances in the development of modular transport vehicles allow deploying multi-purpose vehicles, which enable alternate transport of different demand types. In this study, we propose a novel variant of the pickup and delivery problem, the multi-purpose pickup and delivery problem, where multi-purpose vehicles are assigned to serve a multi-commodity flow. We solve a series of use case scenarios using an exact optimization algorithm and an adaptive large neighborhood search algorithm. We compare the performance of a multi-purpose vehicle fleet to a mixed fleet of single-purpose vehicles. Depending on cost parameters, our findings suggest that in certain scenarios, the total costs can be reduced by an average of 13% when multi-purpose vehicles are deployed, while at the same time reducing total vehicle trip duration and total distance traveled by on average 33% and 16%, respectively. The required fleet size can be reduced by 35% on average when operating multi-purpose vehicles. The results can be used by practitioners and policymakers to determine if the combined service of passenger and freight demand flows with multi-purpose vehicles in a given system will yield benefits compared to existing transport operations.
|
|
| 10. |
- Hatzenbühler, Jonas, et al.
(author)
-
Multi-purpose vehicle assignment for combined passenger and freight transport
- 2022
-
Conference paper (peer-reviewed)abstract
- Recent advances in the development of modular transport vehicles allow deploying multi-purpose vehicles, which enable alternate transport of different demand types. In this study, we propose a novel variant of the pickup and delivery problem, the multi-purpose pickup and delivery problem, where multi-purpose vehicles are assigned to serve a multi-commodity flow. We solve a series of use case scenarios using an exact optimization algorithm and an adaptive large neighborhood search algorithm. We compare the performance of a multi-purpose vehicle fleet to a mixed fleet of single-purpose vehicles. Our findings suggest that total costs can be reduced by an average of 13% when multi-purpose vehicles are deployed, while at the same time reducing total vehicle trip duration and total distance travelled by on average 33% and 16%, respectively. The required fleet size can be reduced by 35% on average when operating multi-purpose vehicles. The results can be used by practitioners and policymakers to determine if the combined service of passenger and freight demand flows with multi-purpose vehicles in a given system will yield benefits compared to existing transport operations.
|
|
| 11. |
- Hatzenbühler, Jonas, et al.
(author)
-
Network design for line-based autonomous bus services
- 2022
-
In: Transportation. - : Springer Nature. - 0049-4488 .- 1572-9435. ; 49:2, s. 467-502
-
Journal article (peer-reviewed)abstract
- The maturing of autonomous driving technology in recent years has led to several pilot projects and the initial integration of autonomous pods and buses into the public transport (PT) system. An emerging field of interest is the design of public transport networks operating autonomous buses and the potential to attract higher levels of travel demand. In this work a multi-objective optimization and multi-agent simulation framework is developed to study potential changes in the network design and frequency settings compared to conventional PT systems when autonomous vehicles (AV) systems are deployed on fixed-route networks. During the optimization process multiple deployment scenarios (network configurations and service frequency) are evaluated and optimized considering the operator cost, user cost and infrastructure preparation costs of the system. User-focused network design and operator-focused network design are studied for a real-world urban area in Sweden. The results provide insights into the network design and level of service implications brought about by the deployment of autonomous bus (AB) when those are integrated in route-based PT systems. We show that the deployment of autonomous buses result with a network design that increases service ridership. In the context of our case study this increase is likely to primarily substitute walking.
|
|
| 12. |
- Hatzenbühler, Jonas
(author)
-
Simulation and optimization of innovative urban transportation systems
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- The ongoing trends of urbanization and e-commerce continuously challenge the existing urban transportation systems. A steadily growing number of people traveling within urban areas, results in more trips taken with public transportation systems. Additionally, the constantly increasing number of urban logistic operations leads to more commercial vehicles in cities. These ongoing trends and the need for more sustainable operations require the design of robust and efficient transportation systems which additionally provide a high level of service for their users. In recent years, two innovative approaches have been proposed to overcome these challenges. That is, first, the use of autonomous buses as a replacement, or an addition to existing public transportation systems, and second, the consideration of consolidating multiple types of demand (i.e. passenger and freight) when planning and designing transportation systems. In this thesis, both approaches are studied and their impact on urban transportation systems is evaluated. This is achieved by developing novel simulation-based optimization models that consider technology-specific cost structures and capture the changed mode of operation for different vehicle technologies.In Papers I and II the deployment of autonomous buses on fixed-line public transportation networks is investigated. Changes in service frequency, vehicle capacity, and metrics corresponding to the level of service for public transportation users due to new vehicle technology are investigated. Furthermore, Paper I explores the transition from conventional public transportation systems to systems operated by autonomous buses, while Paper II investigates the changes in network design due to autonomous bus operations. The developed models are applied to case studies in Kista, Sweden, and Barkarby, Sweden. Two key results can be identified in these studies. First, autonomous bus deployment leads to an increase in service frequency, while waiting time for passengers can be reduced. Second, more passengers are attracted to autonomous bus lines by reducing the access walking distances and increased level-of-service. On more complex networks these trends are amplified. In each of Papers III and IV, a novel pickup and delivery model is proposed. The models consider vehicle concepts which allow for the consolidated transport of multiple demand types. In Paper III the vehicles can serve different types of demand by exchanging purpose-specific modules at dedicated service depots, while in Paper IV individual demand-specific vehicles can form platoons with modular length and varying configuration. The results of the extensive scenario studies and parameter analysis show that for multi-purpose vehicle operations (Paper III) the total costs can be reduced by an average of 13% and for platoon operations (Paper IV) the total costs are reduced by over 48%. In both models, the cost savings stem mainly from a reduction in fleet size, total vehicle trip duration, and the total distance traveled.
|
|
| 13. |
- Hatzenbühler, Jonas
(author)
-
Transition Towards Fixed-Line Autonomous Bus Transportation Systems
- 2020
-
Licentiate thesis (other academic/artistic)abstract
- In the last years the steady development of autonomous driving technology has enabled the deployment of more mature autonomous vehicles. These vehicles have been applied in several pilot projects worldwide, most commonly in the form of small buses. At the same time, the amount of people traveling in especially urban areas is continuously growing, resulting in more trips in the transportation system. An efficient transportation system is therefore required to serve the growing passenger demand. Autonomous buses (AB) are assumed to have lower operational costs and with that public transport (PT) systems can potentially be designed more efficiently to facilitate the increased demand better. In this study, an AB specific simulation-based optimization framework is proposed which allows analyzing the impacts AB have on line-based PT systems. The thesis focuses on the transition from existing PT systems towards line-based PT systems operated partially or exclusively by AB.Existing work on PT service design is extended so that realistic AB systems can be investigated. This is achieved by (i) using AB specific operator cost formulations, (ii) integrating infrastructure costs required for AB operations, (iii) utilizing a dynamic, stochastic and schedule-based passenger assignment model for the simulation of PT networks and by (iv) formulating a multi-objective optimization problem allowing to investigate the stakeholder-specific impacts of AB.In Paper I the effects of AB, concerning service frequency and vehicle capacity, on fixed-line PT networks are investigated. Among other metrics, the changes are evaluated based on differences in level of service and passenger flow. Additionally, the sequential introduction of AB in existing PT systems is studied. The framework addresses a case study in Kista, Sweden. The study confirmed the initial hypothesis that the deployment of AB leads to an increase in service frequency and a marginal reduction in vehicle capacity. Furthermore, it could be seen that the deployment of AB increases the passenger load on AB lines and that passengers can shift from other PT modes towards the AB services.Paper II incorporates a multi-objective heuristic optimization algorithm in the simulation framework. The study investigates changes in transport network design based on the deployment of AB. The differences in user-focused and operator-focused network design are analyzed and the impact of AB on these is quantified. This study is applied to a case study in Barkarby, Sweden where a full-sized, line-based PT network is designed to exclusively operate AB. Among other findings, we show that the autonomous technology reduces the number of served bus stops and reduces the total PT network size. Additionally, average passenger waiting time can be reduced when deploying AB on user-focused PT networks, which in turn leads to a further reduction of user cost.
|
|
| 14. |
- Hatzenbühler, Jonas, et al.
(author)
-
Transitioning towards the deployment of line-based autonomous buses : Consequences for service frequency and vehicle capacity
- 2020
-
In: Transportation Research Part A. - : Elsevier BV. - 0965-8564 .- 1879-2375. ; 138, s. 491-507
-
Journal article (peer-reviewed)abstract
- The deployment of autonomous buses (AB) is expected to have consequences for service design facilitated by its cost function structure. We study the impacts of AB deployment in line-based public transport (PT) systems. In particular, we examine the transition phase where AB is sequentially deployed, involving the selection of lines for which AB will be introduced. To this end, we develop a modeling framework using a dynamic public transportation assignment and operations simulation model that captures users' adaptive path choices. An analytical model is used to determine the initial solutions in terms of service frequency and vehicle capacity for the simulation framework. Due to their different cost function structures, the deployment of AB may be accompanied by changes in the service frequency and vehicle capacity settings and consequently also on passenger flow distribution across the network. Both the simultaneous and the sequential deployment of AB on multiple lines are investigated. Deployment solutions are assessed in terms of the both total operator and user cost. The decision variables are vehicle capacity per line, service frequency per line and vehicle technology per line - i.e. either manually driven or fully automated buses. The framework is applied to a case study in Kista, Stockholm. The study shows that AB service have the potential to attract passengers through improved service provision. A sensitivity analysis is carried out concerning the effects of different cost parameters and demand levels on the deployment of AB in fixed line operations.
|
|
| 15. |
- Pernestål Brenden, Anna, 1978-, et al.
(author)
-
Shared Automated Vehicles - Research & Assessment in a 1st pilot : SARA1 Results report
- 2018
-
Reports (other academic/artistic)abstract
- The technological advance of automated vehicles (AV) is escalating as AVs are expected to have a great potentialto not only cut operation costs but also contribute to the service offered to users. Several pilots and initiatives areplanned in Sweden and especially within the Stockholm metropolitan area. The first is the pilot in Kista plannedby Nobina and involving two vehicles of the type Easy Mile EZ10. Nobina project to run automated bus in Kista,called “Autopiloten” project. SARA1 research project aimed at assessing Kista pilot from behavioural andsystemic perspectives in order to understand the effects and potential of AV:s for shared services. The results ofSARA1 project are important to not only evaluate these pilots from a technical perspective but also to startassessing societal, users and system perspectives Creating knowledge of valuable socio-economic factors intransition to autonomous. In the following we provide, a short description of Kista pilot operations provided byNobina, a state of the art, methods, results, and finally discussion and conclusions.
|
|
