Publications

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...

Summary:
West Seattle (WS) is a part of the city of Seattle, Washington, but is located on a peninsula west of the Duwamish River. The West Seattle High-Rise Bridge serves as the primary connector between West Seattle and the rest of the city, carrying some 84,000 vehicles on average each day. On March 23, 2020, that high bridge was suddenly closed to all vehicle traffic for safety reasons due to greater-than-expected structural deterioration. The high bridge is now being repaired with a...

Summary:
Delivery vehicle drivers are experiencing increasing challenges in finding available curb space to park in urban areas, which increases instances of cruising for parking and parking in unauthorized spaces. Policies traditionally used to reduce cruising for parking for passenger vehicles, such as parking fees and congestion pricing, are not effective at changing delivery drivers’ travel and parking behaviors.

Summary:
As awareness of the vulnerability of isolated regions to natural disasters grows, the demand for efficient evacuation plans is increasing. However, isolated areas, such as islands, often have characteristics that make conventional methods, such as evacuation by private vehicle, impractical to infeasible. Mathematical models are conventional tools for evacuation planning.

Summary:
How can charging infrastructure spark urban freight electrification? With billions of federal dollars to be invested in building out the country’s charging network, EVs (Electric Vehicles) will soon be getting more places to juice up than ever before. The colossal infrastructure undertaking is meant to keep up with surging EV demand, projected to make up a quarter of all new car sales by 2025. For instance, meeting Seattle’s target of putting 174,000 passenger EVs on the road by 2030 will...

Summary:
Transit transfers are a necessary inconvenience to riders. They support strong hierarchical networks by connecting various local, regional, and express lines through a variety of modes. This is true in Seattle, where many lines were redrawn to feed into the Link Light Rail network. Previous transfer studies, using surveys, found that perceived safety, distance, and personal health were significant predictors of transfers.

Summary:
At the core of any flight schedule is the four dimensional (4D) trajectories which are comprised of three spatial dimensions with time added as the fourth dimension. Each trajectory contains spatial and temporal features that are associated with uncertainties that make the prediction process complex. Because of the increasing demand for air transportation, airports and airlines must have optimized schedules to best use the airports’ infrastructure potential.

Summary:
This paper explores the value of providing parking availability data in urban environments for commercial vehicle deliveries. The research investigated how historic cruising and parking delay data can be leveraged to improve the routes of carriers in urban environments to increase cost efficiency. To do so, the research developed a methodology consisting of a travel time prediction model and a routing model to account for parking delay estimates.

Summary:
While freight transportation is a necessary activity to sustain cities’ social and economic life—enabling the movement and deployment of goods and services in urbanized areas—it also accounts for a significant portion of carbon dioxide (CO2) emissions. The urban freight ecosystem is a complex network of agents, both public and private.

Summary:
What does an equitable and just freight system actually look like? We asked UFL members this question at the summer 2022 quarterly meeting. Their responses, shown in the graphic below, cover a wide range of ideas and topics. Some define equity in terms of equal access to the numerous benefits a freight system brings; others call for a reduction in freight costs — like pollution, noise, and traffic — to historically marginalized people. Members differ on who the appropriate stakeholders...

Summary:
This paper provides an approximation method for the optimization of isolated evacuation operations, modeled through the recently introduced Isolated Community Evacuation Problem (ICEP). This routing model optimizes the planning for evacuations of isolated areas, such as islands, mountain valleys, or locations cut off through hostile military action or other hazards that are not accessible by road and require evacuation by a coordinated set of special equipment.

Summary:
While several stakeholders in the private and public sectors are taking actions and drafting roadmaps to achieve sustainable urban freight goals, the urban freight ecosystem is a complex network of stakeholders, achieving such sustainability goals requires the collaboration and coordination between multiple agents. Researchers collected and synthesized views from both the private and public sectors on what is needed to sustainably deliver the last mile and identify roadblocks towards this goal.

Summary:
(This project is part of the Urban Freight Lab’s Technical Assistance Program, where UFL contributes to the project by providing 1:1 match funds in terms of staff and/or research assistants to complete project tasks.) Green Loading Zones (GLZs) are curb spaces dedicated to the use of electric or alternative fuel (“green”) delivery vehicles. Some U.S. cities have begun piloting GLZs to incentivize companies to purchase and operate more green vehicles.

Summary:
Electric vehicles, one of the emerging modes of transportation, are at the forefront of sustainable mobility. In the past years, there has been a rapid rise in EVs, both as private and public transportation modes. Private users are influenced by multiple factors while choosing electric cars as their travel modes. Among them, policy and infrastructure are deemed to be the main influencers globally. These policies and infrastructures vary in different cities.