March/April
2002
Weather:
A Research
Agenda for Surface Transportation Operations
by Gary
G. Nelson and Rudy Persaud
Environmental
Impact
Highway
construction is a very structured, well-planned process; however,
both during construction and afterward, highways exist in a natural
environment that is neither planned nor tamed. Weather is natures
environmental impact on highways, and it can often be
irritating and sometimes be disastrous.
The
effects of weather played a big part in the creation of a federal
government office in 1893 to make inquiry regarding public roads
and to disseminate the information. The Federal Highway Administration
(FHWA) traces its history to the Office of Road Inquiry in Department
of Agriculture. This impetus to create this office came from the lobbying
of the Good Roads Movement, protesting public roads that were, according
to one contemporary slogan, wholly unclassable, almost impassable,
scarcely jackassable!1 The mantra of the Good Roads
proponents was to get the farmers out of the mud by constructing
good roads that made it easier and faster for the farmers to get their
products to market.
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This
speed limit sign covered by flood waters shows a strong relationship
between surface transportation and hydrology. Inland flooding
is a major threat to safety and facilities. It requires effective,
local-scale prediction, and coordinated response from maintenance,
traffic, and emergency management crews.
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In the
21st century, we still need to anticipate weather and to deal with
its adverse weather effects, using information technology and operational
techniques. While the focus has changed from getting out of the mud
to getting out of the muddle of congestion and to improving highway
safety, many promising programs that would do this are, in many ways,
in the same neophytic stage as the Good Roads movement
was a century ago.
Weather
and Highways
The
significance of weather to highways should not be overstated, but
neither should it be lost. The significance of weather is that it
crosscuts almost every goal, use, and operation of highways, and that
is exactly why it is at risk of becoming lost. It has no single organizational
focal point within the highway community. Meteorology, from a transportation
perspective, is focused mostly on the atmosphere and, by extension,
to those who fly in it. There is little focus on the earthly ribbons
of pavement where the majority of commerce flows.
Nevertheless,
weather is an important dynamic factor that affects maintenance, traffic
flow, and disaster response, among other things. To make weather issues
an important part of highway programs, people who manage highway operations
must seek new techniques and intelligent transportation systems that
complement the amazing system of weather-information collection, analysis,
and forecasting that exists in the United States.
Although
weather affects highway planning and design, only highway operations
can deal with the weather threats that change from hour to hour and,
sometimes, from minute to minute. Table 1 summarizes the subclimatic
concerns about weather under each of the highway goals.
Weather
and Operations
The
weather threats and the losses cited in the table cannot be eliminated.
However, as in the case of safety, a systematic and multipronged approach
will have important benefits and will lessen the effect. A focus on
weather and operations could reasonably have a 5-percent to 10-percent
positive effect on any of the goals, and that is easily equivalent
to saving billions of dollars per year across the United States.
The
systematic and multipronged approach has to include operational and
informational integration.
Operational
integration concerns the collaboration of maintenance, traffic, and
emergency management functions, and their relationship to highway
users. Operational management is split among jurisdictions and agencies,
and this presents the challenge of horizontal coordination.
Table
1 — Why Weather Matters to Highway Goals
|
Goal |
Weather
Effects |
Magnitude |
Mobility |
Loss
of capacity through loss of friction, impaired vehicle operation,
reduced visibility, blockages, and equipment outages. |
Weather,
along with incidents and work zones, is a major cause of non-recurrent
highway delay. Average to moderate weather events result in about
a 12-percent travel-time delay. |
Safety |
Cause
of crashes through similar effects as on mobility. |
About
6,600 fatal crashes each year in adverse weather, and 470,000
injury crashes. |
Productivity |
Cause
of increased cost of all productive activities, including highway
operations. |
A
total of $2 billion per year is spent on winter road maintenance,
and damage costs are about $5 billion. Shutdowns due to snow cost
between $20 million and $70 million in an urban region. Loss due
to delay in freight shipments and damage to goods is not well-known. |
Environmental
Quality |
Degradation
of transportation air quality, the cause of anti-icing chemical
use, and the dispersion of all contaminants released on roadways. |
Ozone
attainment depends on only the four highest concentrations each
year, and these critically depend on weather conditions. There
are 15 million tons/yr of road salt applied against ice. Silting
and hazardous materials (hazmat) effects depend on the weather. |
National
Security |
Mobility
of military movements and the vector of any chemical, biological,
or nuclear releases. |
Hard
to assess; however, timely and accurate information is critical. |
Organizational
Excellence |
All
above weather effects potentially decrease customer satisfaction. |
Partners,
customers, and employees will find it difficult getting to destinations
and performing work. |
Intermodal
coordination among all the surface transportation modes is also required.
After all, weather threats do not make modal distinctions.
However,
operational management in surface transportation, unlike in air traffic
management, has little positive control over transportation users,
and user behavior on the transportation system is based mostly on
information that comes from sources other than operational management
authorities. This creates the challenge of vertical coordination between
the operational staff and the public.
Weather
is just one element of the information needed to influence the decision-making
of operational managers and travelers. Informational integration is
about the selection, fusion, and presentation of all relevant information.
However, some fundamental principles apply when dealing with the weather:
- The
effects of weather are mitigated by actions taken with regard to
the highway system, not the weather.
- Those
actions are decided by people (perhaps also by automatic devices),
who must control the appropriate array of tools and techniques.
- Better
predictive information about weather threats is needed to make better
decisions.
A
research agenda to determine how to more effectively use tools and
techniques to deal with weather threats to surface transportation
operations should emphasize the need to make early decisions. If actions
are to be complementary and if scarce resources are to be shared in
times of large-scale disasters, appropriate decisions must be coordinated
so that actions can be integrated.
Much
must be done to coordinate decisions within the transportation community,
as well as between the transportation and weather worlds. The task
of integration is not unique to weather; however, because weather
has a range of scales of predictability, extent, and severity. Linking
the transportation and weather domains also provides interesting opportunities
for interdisciplinary, interagency, and public-private linkages. An
aggressive research agenda could produce fertile synergies.
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Environmental
threats to drivers, such as fog, come from combinations of weather,
surface, and sub-surface conditions. They are dynamic and require
more than static signs to achieve effective driver and highway-operator
responses.
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Where
Is the Surface Transportation Weather Research Agenda?
In September
2000, the deputy secretary of the U.S. Department of Transportation
(DOT), Mortimer Downey, spoke to the National Research Council about
the development of a National Transportation Science and Technology
Strategy, including the need and value of additional weather-related
research and development (R&D).
Advancing
technologies are the primary means by which transportation improvements
can be made to meet 21st century transportation requirements,
Downey said. The development and implementation of these advances
require the coordination of technological progress from diverse areas
and working with stakeholders in each of these areas, including federal
agency programs and industrial participants, as well as state and
local governments.
By nurturing several of these partnership
initiatives, we create an opportunity to bring together crosscutting
research within the federal government and the private sector to support
these transportation goals. Some of the partnerships, such as those
proposed for Enhanced Transportation Weather Services and Transportation
Infrastructure Assurance, are in areas where DOT does not have focused
or well-established R&D programs. These areas, however, serve
a critical function for achieving transportation goals.
In contrast
to surface transportation, the importance of weather research is well-recognized
by authorities in aviation. The Federal Aviation Administration (FAA),
the National Weather Service (NWS), and the U.S. Department of Defense
(DOD) are the Big Three in weather. There are tight operational
links between FAA and NWS, and FAA spends more than $400 million per
year on weather operations and systems acquisition. The Aviation Weather
Research Program under FAA spent $30 million in 2001.
FHWA
is spending about $2 million per year on road/weather research through
the Road Weather Management Program (RWMP), managed by the Operations
Core Business Unit. RWMP also includes participation from the Research,
Development, and Technology Service Business Unit. The funding is
mostly through the intelligent transportation systems (ITS) research
program since there is currently no separate authorization for road
weather research.
Prior
to the initiation of RWMP, there were notable accomplishments, such
as the Strategic Highway Research Program (SHRP) that promoted
the use of Road Weather Information Systems (RWIS) to provide information
for early decisions about anti-icing techniques for winter road maintenance.
However, to a significant extent, the SHRP tools and techniques were
imported from abroad.
Since
the origination of RWMP in the rural ITS program, significant projects
have included:
- The
Foretell consortium. (See FORETELL —
Finally, someone is doing something about the weather! by
Paul Pisano, Public Roads, March/April 2001.)
- The
Surface Transportation Weather Decision Support Requirements (STWDSR)
project.
- The
Maintenance Decision Support System (MDSS) development project.
- Cooperative
Program for Operational Meteorology, Education, and Training (COMET)
research projects.
- Remote
Sensors for Pavement Ice Detection project.
These
projects focus on development of the information thread, from observation
to decision support, primarily for winter road maintenance and on
the subclimatic scales (i.e., for operational management and traveler
information, but not resource planning). Advanced Transportation Weather
Information System (ATWIS) and Foretell are considered first-generation
decision support. ATWIS originated in 1995, outside of RWMP, and Foretell
was the first RWMP operational test awarded in 1997. The projects
have improved RWIS by forecasting road/ weather conditions through
numerical weather modeling and improved dissemination of information
to DOT managers and travelers. Both projects are in multistate, commercial
operation. The STWDSR project, which began in 1999, is aimed at next-generation
requirements that are being demonstrated through the MDSS, now in
its second prototype-development year. The five small COMET grants
awarded in 2000 are for two-year, university-based research into applications
of environmental
sensor stations (ESS). The ice detection project, completed in 2001,
developed infrared sensors that extend the range and detection confidence
of in-pavement ESS.
The
projects listed represent the variety of participants and institutional
arrangements that RWMP is fostering. ATWIS began with university research
at the University of North Dakota and has spun off a private deployment
venture. Foretell started as a three-state consortium with a private
deployment partner. The STWDSR and MDSS projects have developed a
large stakeholder group of DOTs, private vendors, and researchers.
The MDSS project is being conducted by a university research consortium
and by five federal laboratories under the National Oceanic and Atmospheric
Administration (NOAA) and the U.S. Department of Defense.
The
MDSS products will be licensed for private deployment. The COMET projects
are by NWS, state DOTs, and university partnerships. The program has
proven that a little money can leverage significant results and that
more institutions can be enlisted in additional projects for a wider
range of applications.
In
addition to these projects, an important link between highway research
and the weather community has, surprisingly, been created through
the technology of the differential global positioning system (DGPS).
Errors detected by DGPS are determined by the atmosphere and, in particular,
by the integrated precipitable water vapor in the signal paths from
the satellite to ground reference stations. The water vapor data are
an important augmentation to weather observations and can be used
as a detector of precipitation events. Because the DGPS program is
partly under surface transportation auspices, FHWA is working with
the Forecast Systems Laboratory of NOAA, one of the MDSS partners,
on the demonstration of the weather-prediction improvements possible
with the DGPS observations.
The
multimodal implications and the crosscutting between operations and
research mean that there has to be coordination among DOTs surface
modal administrations and its Research and Special Programs Administration
(RSPA). RSPA is currently sponsoring transportation remote-sensing
and radar-based weather-prediction projects. And despite the primarily
above-ground interests of FAA, there are many areas of surface interest
in the Aviation Weather Research Program (for instance, icing and
general improvements in prediction).
In
interdepartmental coordination, the Office of the Federal Coordinator
for Meteorology (OFCM) has played an active role during the last five
years. OFCM was created mainly to be a broker for the large acquisition
programs for satellites, radar, and surface observation systems among
the Big Three. OFCM was in a good position to recognize
the opportunities for surface transportation and has sponsored two
national symposia on surface transportation weather (1999 and 2000),
as well as including the surface administrations in OFCM committees.
Where
Is Surface Transportation Weather Research Going?
Over
the past decade, the Aviation Weather Research Program has built up
to its present level and its ability to map out a long-term program
with experienced university and national laboratory partners. Since
the RWMP and OFCM efforts started only a couple of years ago, the
progress to date for surface transportation is notable.
RWMP
is starting to extend its concern to emergency management (primarily
with respect to hurricane disaster management) and traffic management.
The development of decision-support systems has created strategic
alliances with some of the national laboratories that support the
research of the Big Three. RWMP has been active in the
OFCM efforts and has begun the inter-federal linkages to the large
variety of agencies concerned with surface transportation and weather
information —from the U.S. Department of Agriculture (transportation
of produce) to the U.S. Department
of Energy (movement of hazardous materials) and to the National Aeronautics
and Space Administration (ground movements of space shuttles).
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More
environmental sensor stations, like this one, are needed to
monitor specific road conditions and to support the full range
of warning and prediction needs; however, this is expensive.
Research must answer the questions of how many, where, what
technology, and the tradeoffs with other weather sensors.
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Organizationally,
there are significant challenges to integration of surface transportation
weather. A common research agenda and the pooling of resources require
extensive inter-federal coordination. The Federal-Aid Highway Program
is essentially a federal-state program. This creates a much more diffuse
constituency than for many of the other agencies. The states, through
their planning and research funds, could potentially be a significant
resource. AURORA has already been formed as a pooled-fund consortium
of several states, primarily focused on road/weather concerns.
The
public-private relationships are also a challenge. At present, NWS
maintains a system of public weather information oriented toward safety
and productivity. Its active alliance with aviation fulfills its legislated
mission to serve navigation. There is no comparable service
for commerce, which historically has meant surface transportation.
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New
alliances are being forged between meteorology and the transportation
communities. Differential Global Positioning Systems, such as
this one, being deployed by U.S. DOT and other agencies also
serve to measure atmospheric water vapor. Technology increases
the need for joint research on better weather information and
its applications.
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There
are geophysical reasons for this. Weather-threat information on the
ground and specific to roadways, tracks, or canals involves air-land-water
interactions of a type and scale only now achievable by observational
and predictive capabilities. As a result, value-added meteorological
services (VAMS) have stepped in to fill the gap in tailored
information for surface transportation operators and users.
The
open-system concept, allied with advances in the technology of environmental
prediction and communications, is a key to the issue of informational
integration. An open system technically means that the
entire information system from sensors to graphical prediction displays
has a common structure (architecture) and publicly known ways of connecting
each component of the architecture (standards). An open system is
necessary to achieve the decision-support capability that is the linchpin
for coordinated action within the transportation system. Open systems
convert the proprietary conduits of information to a network of complementary,
but also competing, information processes.
As
the national weather-information system shows, shared observations
are essential to good predictions. Some assimilation applications
require an open system to access all observations. Today, many weather-prediction
models, including those that must operate on a small scale, provide
useful resolution. These need to network with the observations, other
predictive processes (such as deriving road temperature from weather
prediction through heat-balance modeling), the NWS models (for national
boundary conditions), and potentially with each other (to create prediction
ensembles that are better than individual predictions). With an open
system, VAMS can produce better products and reach a larger market.
Over
time, with the appropriate research to identify the gaps in the delivery
of crucial information to decision-makers and to improve the performance
of the whole system, a new public-private allocation of services will
emerge.
The
ITS program, through the National ITS Architecture and its standards,
has championed open systems in surface transportation, and emulates
what is largely an open system on the weather side under NWS auspices.
A
Research Agenda
This
is the time to work out the details of a research agenda. The main
targets of research, as outlined in Table 2, are clear.
The
agenda relates to, but goes beyond, the concerns of existing research
and focuses specifically on application to surface transportation.
The agenda contains a lot to do for everyone — universities,
national research laboratories, states, and private firms. The conduct
of the agenda should follow the model already established for highway
research,
which involves all of these organizations.
However,
the program needs a federal focus. Because of the effective public-private
system of weather information in the United States and the strong
intermodal interests, the inter-federal alignment in the program needs
to be even stronger than in the Federal-Aid Highway Program. A federal
focus within DOT is necessary to conduct the inter-federal coordination
and to mobilize coordinated efforts among the local and private constituencies.
Conclusion
The
Federal-Aid Highway Program, first authorized in 1916, was preceded
by two decades of research and organizing stakeholders. During this
period, many state DOTs were created. An equal period of research
and development preceded the Federal-Aid Highway Act of 1956 that
created the Interstate Highway System and the Federal-Aid Highway
Act of 1962 that required comprehensive urban transportation planning.
In
this era of Internet-speed, research still needs the commitment
to a long-term vision, planning of programs, and development of constituencies.
The research program must harness public, academic, and private partners
to apply advanced weather information and decision support to open-system
products that serve operational techniques.
The
result will be a continual evolution of information and operational
responses to weather. Research on an open system will create new informational
services and uses that are barely imaginable now. The payoff is going
to be in the efficiency, safety, and security of our surface transportation
system that carries the bulk of travelers and commerce.
Reference:
1.Richard
F. Weingroff. A Peaceful Campaign of Progress and Reform: the
Federal Highway Administration at 100, Public Roads,
Vol. 57, No. 2, Autumn 1993.
Table
2 —Transportation Weather Research Targets and Activities
Target
|
Associated
Research |
An
open and national surface transportation observation system
integrated with the international environmental observation
system.
|
- Improved
surface sensors.
- Mobile
sensing.
- Remote
sensing.
- Sensing
platform investment and siting guidance as part of the national
information infrastructure.
|
Timely,
accurate, and relevant transportation condition prediction.
|
- Basic
research in subsurface-roadway-air geophysics.
- Assimilation
techniques for transportation observations.
- Improved
detection and prediction of surface-level precipitation form.
- Prediction-model
ensembling.
- Specialized
models for surface-attribute prediction.
|
Decision
support for coordinated action on all surface transportation
weather threats.
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- Data
source fusion.
- Risk
decision-making.
- Collaborative
decision-making.
- Human
factors in display and information use.
- Adaptive
learning systems.
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Operational
management tools and techniques to make use of weather threat
decision support. |
- A
fundamental operations research effort to understand and quantify
management functions.
- Advanced
maintenance technologies.
- Integration
of weather information into traffic management.
- Integration
of weather information and traffic management into emergency
management.
- Improved
air pollution prediction and response.
- Improved
dispersion/exposure prediction and response to transportation
hazmat (accidental and terrorist) incidents.
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Traveler
and vehicle-operator support for coping with weather threats.
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- Local
hazard warning — media and messages.
- Use
of national driver simulation to test response to weather
threats.
- Human
factors — behavioral, risk, and distraction.
- Vehicle
speed and platoon dynamics under weather conditions.
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Improved
knowledge of the causal relationship between weather and surface
transportation goals and the effectiveness in improving goal performance. |
- Long-term
project evaluation (to control for climatic variability).
- Macro-scale
economic evaluation of weather effects on commerce.
- Augmented
crash data and analysis for weather factors.
- Operations
research of management functions to identify costs and savings.
- Research
on road chemical dispersion and environmental effects.
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An
evolving open network of all information processes connecting
weather to surface transportation decisions. |
- Standards
for transportation weather data and display objects.
- Continuing
evolutionary development tracks.
- Network
survivability.
- Integrated
architectures.
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Gary
G. Nelson
is an intelligent transportation systems (ITS) planner and systems
engineer at Mitretek Systems Inc. in Washington, DC. He has more than
30 years of experience that combines planning and system engineering
in the surface and air modes. Work on the national air traffic management
system, including aviation weather, led to a contract to support of
the FHWA Road Weather Information Program.
Nelson
has a masters degree in engineering and has completed some additional
study at Rensselaer Polytechnic Institute in the doctorate program
in computer and systems engineering.
Rudy
Persaud is a highway research specialist in FHWAs Office
of Operations Research and Development at the Turner-Fairbank Highway
Research Center in McLean, Va. His primary responsibilities are in
the fields of road weather management, rural ITS, and the global positioning
system (GPS). Previously, he worked for South Dakota Department of
Transportation. He was in charge of the states local road system,
and he implemented the GPS and geographic information system (GIS)
program for all roads in South Dakota. Persaud has a bachelors
degree of science and technology in road construction from the University
of South Dakota.
Other Articles in this issue:
"Stone-Walling"
in Arkansas
Arkansas
Combines Best Practices for an Innovative Insterstate Rehabilitation
Program
Small
Investment, Dramatic Dividends — Saving Lives in "Blood
Alley"
National
Review of the Highway Safety Improvement Program
Weather:
A Research Agenda for Surface Transportation Program
Highway
Quality Awards
FHWA
Model Predicts Noise Impacts
Synergy
in Action: FHWA's Transportation Pooled-Fund Program