Title: Quantifying Economic Loses from Travel Forgone Following a Large Metropolitan Earthquake
1Quantifying Economic Loses from Travel Forgone
Following a Large Metropolitan Earthquake
- Caltrans Division of Research and Innovation
- Research Connection Video Conferencing Series
- July 18, 2006
Professor Jim Moore, USC Professor YueYue Fan,
UCD Sungbin Cho, USC/ImageCat Professor Anne
Kiremidjian, LSJU Stu Werner, Seismic Systems and
Engineering Consultants
2Acknowledgements and Disclaimer
- This work was supported primarily by the
Earthquake Engineering Research Centers Program
of the National Science Foundation under award
number EEC-9701568 through the Pacific Earthquake
Engineering Research Center (PEER). - This work made use of the Earthquake Engineering
Research Centers Shared Facilities supported by
the National Science Foundation under award
number EEC-9701471 and by the Federal Highway
Administration through the Multidisciplinary
Center for Earthquake Engineering Research
(MCEER). - Any opinions, findings, and conclusion or
recommendations expressed in this material are
those of the authors and do not necessarily
reflect those of the National Science Foundation
or the Federal Highway Administration or the
California Department of Transportation.
3Key References
- Moore, II, J.E, S. Cho, YY. Fan, and S. Werner
(2006) Quantifying Economic Loses from Travel
Forgone Following a Large Metropolitan
Earthquake, PEER Report 2007/, Berkeley, CA
Pacific Earthquake Engineering Research Center,
forthcoming. - Kiremidjian, A., J. E. Moore, II, YY. Fan, N.
Basoz, O. Yazali, and M. Williams (2006) Pacific
Earthquake Engineering Research Center Highway
Demonstration Project, PEER Report 2006/02,
Berkeley, CA Pacific Earthquake Engineering
Research Center, forthcoming. - Werner, S. D., C. E. Taylor, S. Cho, J. P.
Lavoie, C. K. Huyck, C. Eitzel, R. T. Eguchi, and
J. E. Moore, II (2004) New Developments in
Seismic Risk Analysis of Highway Systems, Paper
2189, Proceedings of the 13th World Conference on
Earthquake Engineering, Vancouver, BC. - Cho, S.B., YY. Fan, and J. E. Moore, II (2003)
Modeling Transportation Network Flows as a
Simultaneous Function of Travel Demand,
Earthquake Damage, and Network Level of Service,
Advancing Mitigation Technologies and Disaster
Response for Lifeline Systems, Proceedings of the
6th US Conference, Long Beach, CA.
4Motivation
- Caltrans District 7 was immediately attacked in
the press following the Northridge Earthquake. - Some facilities had failed.
- The media has a tendency to equate bad outcomes
with bad decisions. - Repair of the I-10 bridges following the
Northridge Earthquake in 1994 produced two
controversies. - Bonuses paid to C. C Meyers to accelerate the
work were thought by some to be a poor use of
public resources. - Some prominent earthquake engineers criticized
the design standards of the new bridges as not
sufficiently earthquake resistant.
5Insights
- There is more to a facilitys importance than
Average Daily Traffic. - Available redundant capacity in the network
should be accounted for. - Prioritizing bridge retrofits (or
reconstructions) is an exercise in network
design. - Resources are scarce.
- We cannot afford to design every transportation
structure in the inventory to withstand a maximum
credible earthquake. - District 7 still did one hell of a fine job
deploying innovative, low cost retrofits prior to
the Northridge Earthquake. - There is considerable serious work to be done at
the interface of transportation engineering and
earthquake engineering.
6Stages of Interdisciplinary Work
- Your fields problems must be trivial, otherwise
my own fields methodologies would have already
addressed them. - Your field focuses on substantive problems, but
these must be intractable, otherwise my fields
methodologies would have already addressed them. - Denial, Anger, Bargaining, and Acceptance
- Your field includes methodologies that might be
relevant to standing problems in my own field. - Understanding your fields methods helps define
new problems and opportunities in my own field.
7Imposing Pre-earthquake Travel Demand on a
Post-earthquake Network
- Fails to account for
- Movement along the travel demand curve, or
- Shifts in the travel demand curve.
- Overestimates post-earthquake travel volumes.
- Generates unrealistic volume/capacity ratios.
- Generates unrealistic travel delays.
- Is a source of embarrassment for transportation
engineers who are attempting to persuade
earthquake engineers of the importance of
transportation engineering.
8Applying Standard Transportation Planning Models
to Earthquakes
9Treating Post-earthquake Travel Demand as a
Function of Network Level of Service
- Adds considerable economic and behavioral realism
by allowing equilibria in the market for
transportation to shift along a conventional
demand curve. - Better estimates post-earthquake travel volumes.
- Generates wholly realistic volume/capacity
ratios. - Generates wholly realistic, yet elevated
zone-to-zone travel delays.
10Stepping Back Recognizing that Travel Demand is
a Function of Level of Service
11Treating Travel Demand as a Function of Network
Level of Service
- Substantially complicates network assignment
calculations intended to identify user
equilibrium flows. - Is outside standard practice, but almost within
the grasp of standard computational tools, and
should likely become standard practice. - Generates an apparent reduction in total travel
delay due to reduced travel demand, thereby - Making it appear that earthquakes improve
transportation system performance, and - becoming a source of embarrassment for
transportation engineers who are attempting to
persuade earthquake engineers of the importance
of transportation engineering.
12Cumulative Distribution of Post-earthquake
Volume/Capacity Ratios
13REDARS (Risks from Earthquake Damage to Roadway
Systems)
- Software package supplied by the Federal Highway
Administration (FHWA). - An advanced seismic risk analysis (SRA) tool that
enable users to better plan for and respond to
earthquake emergencies. - Methodologys risk-based framework uses
- models for seismology and geology, engineering
(structural, geotechnical, and transportation),
repair and reconstruction, system analysis, and
economics to - estimate system-wide direct losses and indirect
losses due to reduced traffic flows and increased
travel times caused by earthquake damage to the
highway system.
14REDARS (cont.)
- Developed by FHWA and the Multi-Disciplinary
Earthquake Engineering Research Center (MCEER) as
a future public-domain software package. - REDARS 2.0 incorporates a version of the Variable
Demand Model operationalized in the PEER Highway
Demonstration Project. - Successfully applied to the
- Memphis, TN highway network, a location that is
vulnerable to a repeat of the 1812 New Madrid
zone earthquakes, and to a - limited portion of Caltrans highway network
extending from Fairfield to Oakland. - The California project was intended to transfer
technical expertise from the developer community
within FHWA and MCEER to Caltrans.
15REDARS methodology
16REDARS Seismic Risk Analysis (SRA) Modules
17The PEER Variable Demand Model is incorporated
into REDARS 2.0
- For a given earthquake scenario and network data,
REDARS 2.0 sequentially analyzes - ground motion
- bridge / tunnel / roadway damage states
- network configurations
- executes a VDM analysis of network level of
service - Reports results
- 7 days
- 60 days
- 150 days following the event.
18Endogenizing Travel Demand
- Requires parameterization of travel demand
curves, - Which can be done on a zone-to-zone basis
- Based on baseline travel demands and costs, and
- A gravity model calibration, or equivalent
calculation. - But which ideally would be based on a model of
the urban activity system - Makes it possible to determine
- The total increased delay experienced by
travelers who remain on the network, and - The number of trips eliminated from the network,
and their value to the people who were previously
making them, thereby - Providing a long sought after source of
credibility for transportation engineers who are
traveling in the company of earthquake engineers.
19Economic Losses Linked to Network Level of
Service Following an Earthquake
20Obtaining Empirical Estimates of Coefficients for
Monotone Travel Demand Functions
21Empirical Travel Demand Curves are Non-monotonic
22REDARS 2.0 Import Wizard
- Combines federal, state, and local data from
public sources to generate transportation network
data for study area. - Public data sources used to compile the network
database consist of - National Highway Planning Network (NHPN) from the
Federal Highway Ad-ministration (FHWA), - FHWA Highway Performance Monitoring System (HPMS)
- FHWA National Bridge Inventory (NBI),
- Bay Area transportation analysis zone map from
the Metropolitan Transportation Commission (MTC),
and - MTC 1998 Bay Area (passenger) trip table (Peak 4
hours).
23The Bay Area Highway Network Model Characterized
by the Import Wizard Includes
- 10,154 directional links
- 3,288 nodes,
- 1,136 Travel Analysis Zone (TAZ) centroids,
- 1,475 bridges, and
- eight tunnels.
24The San Francisco Bay Area Roadway Network
Characterized by the REDARS 2.0 Import Wizard
25Hayward Fault Scenario Earthquake
- Moment magnitude 7.1 event along the Hayward
fault. - Epicenter at -122.0866 o / 37.7266 o in decimal
longitude and latitude. - REDARS 2.0 estimates
- 92 bridge collapses
- 466 damaged bridges
- 36 links subject to pavement failures due to
liquefaction - Full reconstruction or repair in 231 days,
assuming no constraints on resources
26Bridge and Link Damage States Associated with the
Hayward Fault Scenario Earthquake
27Variable Demand Model Algorithm Performance
- Four minutes of calculations using desktop
computing resources. - Travel demands associated with only 20 of the
origin-destination zone pairs have converged to
values consistent with the associated set of
empirically estimated travel demand functions. - The flows associated with these zone pairs
account for 95 percent of the total trips in the
system. - The remaining 80 of the zone pairs account for
only about 5 percent of the trips.
28Variable Demand Model is Effective for Most
travel, but not Most Zone Pairs
29(No Transcript)
30Total Household Transportation Impacts
31Extensions
- Treating freight flows.
- Accounting for demand shifts, as opposed to
movements along a demand curve. - Decision support and network design.
32Freight Trip Generation
- MTC does have freight origin-destination tables
available. - Alternatively, employment data from the 2000
Census Transportation Planning Package (CTPP) for
the San Francisco Bay Area can be used to
construct intra-regional freight trip generation
estimates. - The CTPP includes employment data by economic
sector and by place of employment (by Traffic
Analysis Zone). - Commodity flows between industries can be used to
estimate freight trip productions and
attractions. - To convert this aspatial information to spatial
flows, disaggregate and assign these interactions
to each TAZ based on 2000 CTPP employment by TAZ
and by sector. - Interregional flows are estimated by
- Identifying network locations associated with
inter-regional freight movement, including
seaports, airports, rail yards, and highway
network entry points, and - Assembling freight tonnage data for inbound and
outbound freight for each of these sites,
33Movement Along a Demand Curve versus a Shift in
Demand
34Network Design Problem
- Broadly stated, our research goal is to find,
subject to certain resource constraints, which
network components should be retrofitted, and
where new components should be added so that the
overall performance of any metropolitan
transportation system is maximally improved. - This well-defined network design problem is
important in the transportation network
literature (Yang and Bell 1998).
35Deterministic Network Design is Reasonably
Difficult
- Individual users and network planners do not have
the same objectives. Consequently, the network
design problem involves multiple levels of
optimization. - At the upper level, the system planner makes
decision on resource allocation to achieve the
best system performance. - At the lower level, the network users make their
travel decision based on their individual travel
preferences. - For a large network, this kind of network design
problem is computationally challenging.
36Stochastic Network Design is Even More Difficult
- Uncertainty makes the pre-event network design
problem very challenging. The problem has been
formulated (Yang and Bell 1998), but never
treated at a realistic scale. - Subject to budget constraints, the objective is
to find the transportation network configuration
on which user equilibrium flows produce the
minimum expected total congestion. - This stochastic version of the problem is an
embedded optimization problem with a tri-level
structure. - The upper level is the decision by the network
authority, in this case a pre-event retrofit or
reconstruction decision. - The intermediate level outcome, a function of the
upper level decision, is a random result of
nature. - The lower level, a function of the upper level
decision and the intermediate outcome, is the
decision by the network user.
37Complexity
- Assuming that retrofitting transportation
structures is not a matter of degree, but rather
a binary decision - then a network with M transportation structures
supporting its links presents 2M retrofit
options. - A random act of nature converts the network to a
collection of L lt M links. - The total number of possible networks to be
considered is thus an impossibly large value, - Explicit enumeration of options is out of the
question, so now what?