Modeling

The Ethical Challenges and Professional Responses of Travel Demand Forecasters

Brinkman, Anthony P.
2003

Thirty years ago scholars first presented convincing evidence that local officials use biased travel demand forecasts to justify decisions based on unstated considerations. Since then, a number of researchers have demonstrated convincingly that such forecasts are systematically optimistic-often wildly so-for reasons that cannot be explained solely by the inherent difficulty of predicting the future. Why do modelers-professional engineers and planners who use quantitative techniques to predict future demand for travel and estimate its potential impact on built and proposed transportation...

Compliance, Congestion, and Social Equity: Tackling Critical Evacuation Challenges through the Sharing Economy, Joint Choice Modeling, and Regret Minimization

Wong, Stephen D.
2020

Evacuations are a primary transportation strategy to protect populations from natural and humanmade disasters. Recent evacuations, particularly from hurricanes and wildfires, have exposed three critical evacuation challenges: 1) persistent evacuation non-compliance to mandatory evacuation orders; 2) poor transportation response, leading to heavy congestion, slow evacuation clearance times, and high evacuee risk; and 3) minimal attention in ensuring all populations, especially those most vulnerable, have transportation and shelter. With ongoing climate change and increasing land development...

An Analysis of Port Selection

Malchow, Matthew Brian
2001

The objective of this research is to study the competition among ports. In particular we study the relation between port characteristics and port market share of maritime traffic. Maritime carriers make two primary decisions that affect ports. In the long-term, they assign vessels to routes. In the short-term, they assign each shipment to a vessel and, with that vessel, a port. In this research, we assume that vessel schedules are fixed and model the assignment of shipments as a function of the attributes that describe each port. For a carrier, some assignments are simpler than other...

Dynamic Stochastic Optimization Models for Air Traffic Flow Management

Mukherjee, Avijit
2004

This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular...

Optimal Infrastructure System Maintenance and Repair Policies with Random Deterioration Model Parameters

Park, Sejung
2004

Accurate facility deterioration models are important inputs for the selection of Infrastructure Maintenance, Repair, and Reconstruction (MR & R) policies. Deterioration models are developed based on expert judgment or empirical observations. These resources, however, might not be sufficient to accurately represent the performance of infrastructure facilities. Incorrect deterioration models may lead to wrong predictions of infrastructure performance and selection of inappropriate MR & R policies. This results in higher lifecycle costs. Existing infrastructure MR & R...

Trust and Compassion in Willingness to Share Mobility and Sheltering Resources in Evacuations: A case Study of the 2017 and 2018 California Wildfires

Wong, Stephen D
Walker, Joan L
Shaheen, Susan A
2020

Advances in the sharing economy – such as transportation network companies (e.g., Lyft, Uber) and home sharing (e.g., Airbnb) – have coincided with the increasing need for evacuation resources. While peer-to-peer sharing under normal circumstances often suffers from trust barriers, disaster literature indicates that trust and compassion often increase following disasters, improving recovery efforts. We hypothesize that trust and compassion could trigger willingness to share transportation and sheltering resources during an evacuation.To test this hypothesis, we distributed a survey to...

Willingness of Hurricane Irma evacuees to share resources: a multi-modeling approach

Wong, Stephen D
Yu, Mengqiao
Kuncheria, Anu
Shaheen, Susan A
Walker, Joan L
2022

Recent technological improvements have greatly expanded the sharing economy (e.g., Airbnb, Lyft, and Uber), coinciding with growing need for transportation and sheltering resources in evacuations. To understand influencers on sharing willingness in evacuations, we employed a multi-modeling approach across four sharing scenarios using three model types: 1) four binary logit models that capture each scenario separately; 2) a multi-choice latent class choice model (LCCM) that jointly estimates multiple scenarios via latent classes; and 3) a portfolio choice model (PCM) that estimates...

Improving City Mobility through Gridlock Control: an Approach and Some Ideas

Daganzo, Carlos F.
2005

This paper examines the effect of gridlock on urban mobility. It defines gridlock and shows how it can be modeled, monitored and controlled with parsimonious models that do not rely on detailed forecasts. The proposed approach to gridlock management should be most effective when based on real-time observation of relevant spatially aggregated measures of traffic performance. This is discussed in detail. The ideas in this paper suggest numerous avenues for research at the empirical and theoretical levels. An appendix summarizes some of these.

City-Scale Transport Modeling: An Approach for Nairobi, Kenya

Daganzo, C. F.
Li, Yuwei
Gonzales, Eric J.
Geroliminis, Nikolas
2007

Traffic congestion poses problems for cities around the world, especially in rapidly growing and motorizing cities like Nairobi, Kenya. We show here how we plan to use in the context of Nairobi a new theory that relates the mobility provided by a city’s street network to the number of vehicles on the network (including private cars and public transport) and to key aggregate descriptors of both the street infrastructure and the public transport services. Conventional micro-simulation models require vast quantities of data and produce unreliable detailed results. The new theory asserts that...

Multimodal Traffic at Isolated Signalized Intersections: New Management Strategies to Increase Capacity

Xuan, Yiguang
Gayah, Vikash
Daganzo, Carlos
Cassidy, Michael
2009

New ideas are explored for managing multimodal traffic on isolated approaches to signalized intersections. Strategies are proposed that both: segregate distinct modes along the approach, and more effectively resolve the disruptive capacity-reducing conflicts that arise between through moving and turning traffic traveling in adjacent lanes. The proposed schemes produce capacities that consistently and significantly exceed those of conventional intersection treatments, and reduce travel delays for all modes. Observations at a real intersection support these claims.