Project Number:
08-19
Research Project:
Identification and Evaluation of Major Issues Involving the Impact of Global Climate Change on Transportation Systems
P.I. Name & Address:
Sami F. Masri
University of Southern California
Viterbi School of Engineering
Los Angeles, CA 90089-2531
Email: masri@usc.edu
Website: http://www.usc.edu/dept/civil_eng/dept/faculty-staff/faculty-directory/masri-sami.htm
Phone: (213) 740-0602
Fax: (213) 740-3984
Co-P.I.
Roger Ghanem
University of Southern California
Viterbi School of Engineering
Los Angeles, CA 90089-2905
Email: ghanem@usc.edu
Website: http://ae-www.usc.edu/personnel/ghanem/index.shtml
Phone: (213) 740-9528
Fax: (213) 740-3984
Project Objective:
There is a dearth of published studies that deal with the implications of long-range climate change in regard to transportation systems. This proposal aims to identify the significant issues likely to be induced by the expected global climate change in so far as transportation systems in the USA are concerned. Not only will the direct climate change effects on engineered transportation infrastructure components be identified and promising solutions suggested, but a clear roadmap will be established, using the Los Angeles transportation network as a template, which will encompass the numerous tasks that are needed for the modeling framework of a useful simulation tool for decision makers. Such a modeling tool will be capable of dealing with a variety of inputs, corresponding to different existing or needed databases, that encapsulate the probabilistic nature of the many uncertain parameters that influence the operation of extended and interacting transportation networks.
A significant output of the proposed research effort (when all its planned phases are eventually implemented) is to determine the relative sensitivity of the simulation model to various controlling (uncertain) parameters that characterize the evolution of traffic and goods flow within regional networks, or throughout national networks, thus providing decision makers with advance planning options so that they may start collecting the types of relevant data whose availability will reduce the uncertainty in quantifying specific decision variables, and hence improve their ability to make optimal policy decisions to insure a resilient transportation system.
Task Descriptions
Task 1: Review and Evaluate Climate Change-Induced Factors on Transportation Networks
This task will focus on performing a comprehensive literature review so as to evaluate all the significant factors that are relevant for assessing the climate change impact on transportation networks. Among the anticipated factors are: temperature, precipitation, hurricanes, trade volume of USA with major international partners, and loads at major ports.
Task 2: Develop Long-Range Roadmap for a Probabilistic Simulation Tool to Represent and Quantify Uncertainties in Climate Induced Effects on the Transportation System
Considering the many subtasks needed for a sophisticated and comprehensive simulation and visualization tool to represent the broad range of uncertainties underlying the modeling of climate-induced direct and indirect effects on transportation system infrastructure, a long range roadmap will be developed in which a flexible framework will be established to allow the convenient incorporation (in follow-up phases of this study) of a variety of modules and "tool boxes" (currently available or as yet to be developed) that will provide inputs and outputs to components of the simulation tool. Among these modules would be ones that furnish climate model predictions of environmental conditions at certain locations; models of transportation networks (of varying levels of coverage and sophistication); economic activity models that relate to transportation loads; engineering materials degradation models; structural damage accumulation models; etc. The PIs recognize that, while some climate models and transportation network models, material damage models, and damage accumulation models do exist, developing a sophisticated version of a regional network is a huge undertaking that requires a considerable, sustained effort over a long period of time. The aim of the subtasks listed below is to identify the major building blocks that need attention for full implementation of a high-resolution simulation tool, and to determine the dominant features that they are required to possess. Consequently, the aim of the listed subtasks is to identify and delineate the major elements of the simulation tool, whose overall methodology will be illustrated and demonstrated by means of simplified versions of some representative types of needed modules for the proposed simulation tool.
Sub-Task 2.1: Identify Initial Models for Evolution of Climate Factors
Identify initial models for the long-term evolution of trends and fluctuations for climate factors. These models will be in the form of non-Gaussian and non-stationary spatio-temporal stochastic processes (Sakamoto and Ghanem, 2002; Soize and Ghanem, 2004). Specifically, the needed climate factors (such as temperature, rain, wind) will be treated as correlated stochastic processes, whose joint probabilistic properties will be extracted from published climate model outputs.
Sub-Task 2.2: Determine Major Attributes of National Transportation Network Model for Major Cities and Ports
This phase of the study will focus on how best to represent the main traffic arteries (interstate network, US highways, and freeways in metropolitan areas) and their inter-connections to major ports. The model information will include not only the topology of the network (connectivity of segments), but also geometry information about capacities, and the location of bridges and associated waterways. Available databases from regional, state and national sources will be utilized to the full extent possible. Among the potential sources of information would be the Southern California Association of Governments (SCAG), the California Department of Transportation (Caltrans), and the Federal Highway Administration (FHWA).
Task 2.3: Development of Risk Models for Network Segments
In order to provide transportation planning authorities with some quantitative measures of the impact of climate effects on the engineered infrastructure, simplifying assumptions will be made to capture the dominant effects of different parameters that have a significant influence on the network operation. For example, rather than focus on the minute detail of deterioration science that governs the evolution of different levels of damage intensity, type, location, etc, the combined effects of a certain scenario will be expressed in term of an "impedance" function that captures the deleterious effects of infrastructure damage in the form of retardation in the traffic flow ("flux") within a target network segment. The network representation will include the characterization of the impedance, the capacity, and the probability of failure for each edge in the network. This probability of failure will be related to climate change factors and to strength (e.g. material) of segment.
Task 2.4: Development of Objective Functions and Optimization Procedures
This task will focus on the formulation of a broad set of objective functions both at the component level and the system level of the transportation network. This will provide flexibility in the development of well-adapted and efficient global optimization algorithms (Masri and Werner, 1985; Smith et. al. 1998; Masri et. al. 1995). Moreover, the choice of objective functions will be designed to enable the decision maker to emphasize various measures of performance of the network, such as point-to-point connectivity or network throughput.
Task 2.5: Development of Scenario Generation Capability from Probabilistic Distributions
A procedure will be developed to allow a user of the simulation software to conveniently specify a list of assumptions that govern the various input parameters for a given simulation study. A means will be developed to allow the convenient selection from a database that is constructed so as to provide representative samples from assumed probabilistic distributions related to needed scenario generation.
Task 2.6: Development of a GIS Interface for Decision Support
The proposed methodology and algorithms will be built around a GIS. While providing a clear and easy interface for decision makers, the GIS will also permit access to a large set of sophisticated resources available in various government and commercial databases.
Task 2.7: Development of Libraries of Advanced Technology Solutions
This library will permit the development of alternative scenarios reflecting the availability of advance technologies for mitigating climate-induced effects on network components. These technologies will include structural control, advanced materials, and sensor-based monitoring and condition assessment. The effects of these technologies on the various network components will be represented by modules that interface with the network impedance module.
Task 2.8: Guidelines for Life Cycle Management that Account for Climate Change
We will utilize the completed simulation tool to provide guidelines for decision makers and DOT officials that are relevant to the management of current assets and the construction of future assets so as to optimize their life cycle cost, taking into account climate change trends and fluctuations.
Tasks 2.6, 2.7, and 2.8 will not be addressed in this year's effort and are included here to provide a context for the proposed effort.
Task 3: Perform Sensitivity Analysis of Quantities of Interest
Analysis will be performed to quantify the sensitivity of the probabilistic predicted performance metrics with respect to the probabilistic descriptors of the climate change control factors. The proposed simulation procedure (sketched in the flowchart shown in the adjoining figure) requires the development of the analysis modules described in the next few paragraphs. A rudimentary version of each of these modules will be developed as part of this initial effort that is sufficient to demonstrate the significant characteristics of the proposed decision support system.
Milestones, Dates:
September 1, 2007 – August 31, 2008
Total Budget:
$90,000
Student Involvement:
One student at 50% for 9 months
Relationship to Other Research Projects:
Related to 01-02; part of the infrastructure focus area
Technology Transfer Activities:
Project report will be posted soon
Potential Benefits of the Project:
This research will examine the effects of climate change on transportation systems at both the regional and national level.
TRB Keywords:
Climate Change, Goods Movement, GIS, Transportation Network, Los Angeles
