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Urban Freight Lab

Publication Type: Article

Article

Deliver it All: In an Age of Expanding Online Commerce, Is Home Delivery Greener Than Sending Full Truckloads of Goods to Stores and Then Customers Driving to Them?

URL: http://www.scmr.com/article/deliver_it_all
Publication: Supply Chain Management Review
Pages: 20-26
Publication Date: 2016
Summary:

In an age of expanding online commerce, is home delivery greener than sending full truckloads of goods to stores and then customers driving to them? A detailed regional study finds compelling answers.

Readers who were teenagers in the 1980s may remember driving to a Sam Goody store to buy music. You probably also remember your disappointment when sometimes the tape or CD wasn’t in stock when you arrived. Perhaps you returned to your car and headed for Tower Records to try your luck there.

Your kids would probably find this story inconceivable today. The advent of the internet has profoundly altered consumer expectations. Immediate gratification is getting closer by the day; you can now obtain your favorite song in seconds, and order and receive physical goods in as little as a few hours in some urban areas.

Today’s ninth-grader expects to find any product she wants in seconds and order it right away on her smartphone. What’s more, she expects that the order will be accurate, complete, well-packed, and easy to return if desired.

Authors: Dr. Anne GoodchildBill Keough, Erica Wygonik
Recommended Citation:
Goodchild, Anne Victoria, Erica Wygonik, and Bill Keough. "Deliver it all." Supply Chain Management Review (2016).
Article, Special Issue

Urban Logistics: From Research to Implementation

 
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URL: https://doi.org/10.1016/j.rtbm.2022.100913
Publication: Research in Transportation Business & Management (RTBM)
Volume: 45 (A)
Publication Date: 2022
Summary:

To address the accessibility and sustainability challenges of urban logistics it is important to consider urban logistics from a number of perspectives.

This includes considering:

  • spatial context i.e. not focusing solely on the urban center or core but also in terms of actions taken in broader logistics and supply chain management.
  • stakeholders i.e. including all key decision makers and constituents.
  • complexity and heterogeneity of activities (range of vehicles used, the products carried, location of distribution centers, and the variety found in city size, form, and governance).

This diversity of perspectives, and their influence on the urban freight system, makes it challenging to identify simple solutions to problems.

A number of forces are also at work impacting change in the urban logistics system. Technological innovation affecting urban logistics includes digitalization, e.g. the Internet of Things (important in terms of connected objects) and big data. These developments are already established and beginning to have an impact or at least implications in the field of urban logistics and freight transport. However, problems will not be solved by technology alone and it is essential to understand how behavior (at the individual and corporate level) influences outcomes and needs to change. Research needs to address interactions between stakeholders and the role of city authorities in promoting innovation and change.

Cities are complex environments and urban logistics has to adapt to these demands. The complexity of cities also gives rise to a debate about the extent to which problems (and their possible solutions) may be considered context-specific. This leads to questions relating to how initiatives should be scaled up to gain greater traction in dealing with challenges now and in the future. It is important to learn as much as possible from the high number of projects and new services that have been implemented in cities over the past ten years. These range from initiatives related to electric vehicles, through locker box systems and the role of the receiver in making change happen. How to learn and then apply the lessons from projects is an important question. In many cases it has been argued that the underlying business model has not been addressed successfully leading to the problem of projects lasting only as long as some form of project funding is available.

Authors: Dr. Anne Goodchild, Michael Browne (University of Gothenburg)
Recommended Citation:
Michael Browne, Anne Goodchild. Urban Logistics: From Research to Implementation, Research in Transportation Business & Management, Volume 45 (A) 2022, 100913, ISSN 2210-5395, https://doi.org/10.1016/j.rtbm.2022.100913.
Article

A Framework to Assess Pedestrian Exposure Using Personal Device Data

 
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URL: https://doi.org/10.1177/1071181322661319
Publication: Human Factors and Ergonomics Society
Volume: 66 (1)
Pages: 320 - 324
Publication Date: 2022
Summary:

Capturing pedestrian exposure is important to assess the likelihood of a pedestrian-vehicle crash. In this study, we show how data collected on pedestrians using personal electronic devices can provide insights on exposure. This paper presents a framework for capturing exposure using spatial pedestrian movements based on GPS coordinates collected from accelerometers, defined as walking bouts. The process includes extracting and cleaning the walking bouts and then merging other environmental factors. A zero-inflated negative binomial model is used to show how the data can be used to predict the likelihood of walking bouts at the intersection level. This information can be used by engineers, designers, and planners in roadway designs to enhance pedestrian safety.

Authors: Haena Kim, Grace Douglas, Linda Ng Boyle, Anne Moudon, Steve Mooney, Brian Saelens, Beth Ebel
Recommended Citation:
Douglas, G., Boyle, L. N., Kim, H., Moudon, A., Mooney, S., Saelens, B., & Ebel, B. (2022). A Framework to Assess Pedestrian Exposure Using Personal Device Data. Proceedings of the Human Factors and Ergonomics Society Annual Meeting. https://doi.org/10.1177/1071181322661319
Article

Local Area Routes for Vehicle Routing Problems

 
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URL: https://arxiv.org/pdf/2207.04520.pdf
Publication: arXiv
Publication Date: 2022
Summary:
In this research we consider an approach for improving the efficiency and tightness of column generation (CG) methods for solving vehicle routing problems. This work builds upon recent work on Local Area (LA) routes. LA routes rely on pre-computing (prior to any call to pricing during CG) the lowest cost elementary sub-route (called an LA arc) for each tuple consisting of the following: (1) a customer to begin the LA arc, (2) a customer to end the LA arc, which is far from the first customer, (3) a small set of intermediate customers nearby the first customer. LA routes are constructed by concatenating LA arcs where the final customer in a given LA arc is the first customer in the subsequent LA arc. A Decremental State Space Relaxation (DSSR) method is used to construct the lowest reduced cost elementary route during the pricing step of CG. We demonstrate that LA route based solvers can be used to efficiently tighten the standard set cover vehicle routing relaxation using a variant of subset row inequalities (SRI). However, SRI are difficult to use in practice as they alter the structure of the pricing problem in a manner that makes pricing difficult. SRI in their simplest form state that the number of routes servicing two or three members of a given set of three customers cannot exceed one. We introduce LA-SRI, which in their simplest form state that the number of LA arcs (in routes in the solution) including two or more members of a set of three customers (excluding the final customer of the arc) cannot exceed one. We exploit the structure of LA arcs inside a Graph Generation based formulation to accelerate convergence of CG. We apply our LA-SRI to CVRP and demonstrate that we tighten the LP relaxation, often making it equal to the optimal integer solution, and solve the LP efficiently without altering the structure of the pricing problem.

 

Authors: Amelia Regan, Udayan Mandal, Julian Yarkony
Recommended Citation:
Mandal, U., Regan, A., & Yarkony, J. (2022). Local Area Subset Row Inequalities for Efficient Exact Vehicle Routing. arXiv preprint arXiv:2209.12963.
Article

Local Area Subset Row Inequalities for Efficient Exact Vehicle Routing

 
Download PDF  (1.44 MB)
URL: https://doi.org/10.48550/arXiv.2209.12963
Publication:  arXiv e-prints (2022): arXiv-2209
Publication Date: 2022
Summary:
In this research we consider an approach for improving the efficiency and tightness of column generation (CG) methods for solving vehicle routing problems. This work builds upon recent work on Local Area (LA) routes. LA routes rely on pre-computing (prior to any call to pricing during CG) the lowest cost elementary sub-route (called an LA arc) for each tuple consisting of the following: (1) a customer to begin the LA arc, (2) a customer to end the LA arc, which is far from the first customer, (3) a small set of intermediate customers nearby the first customer. LA routes are constructed by concatenating LA arcs where the final customer in a given LA arc is the first customer in the subsequent LA arc. A Decremental State Space Relaxation (DSSR) method is used to construct the lowest reduced cost elementary route during the pricing step of CG. We demonstrate that LA route based solvers can be used to efficiently tighten the standard set cover vehicle routing relaxation using a variant of subset row inequalities (SRI). However, SRI are difficult to use in practice as they alter the structure of the pricing problem in a manner that makes pricing difficult. SRI in their simplest form state that the number of routes servicing two or three members of a given set of three customers cannot exceed one. We introduce LA-SRI, which in their simplest form state that the number of LA arcs (in routes in the solution) including two or more members of a set of three customers (excluding the final customer of the arc) cannot exceed one. We exploit the structure of LA arcs inside a Graph Generation based formulation to accelerate convergence of CG. We apply our LA-SRI to CVRP and demonstrate that we tighten the LP relaxation, often making it equal to the optimal integer solution, and solve the LP efficiently without altering the structure of the pricing problem.

 

Authors: Amelia Regan, Udayan Mandal, Julian Yarkony
Recommended Citation:
Mandal, U., Regan, A., & Yarkony, J. (2022). Local Area Subset Row Inequalities for Efficient Exact Vehicle Routing. arXiv preprint arXiv:2209.12963.