Transportation Systems and Winter Operations In Japan
FHWA International Technology Exchange Programs
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Winter Maintenance Equipment
Advanced Maintenance Equipment
Measuring and Communicating Winter Road Conditions
Coordinated Use of Weather Forecast Data
Use of Winter Maintenance Decision Support Systems
Performance Evaluation of Winter Maintenance Operations
Winter Traveler Information
Driver Education for Winter Conditions
The Japanese organizations the scanning team visited were thorough in their
preparations for the team's visit and generous in sharing their experiences
and advances. The visits with European researchers also yielded valuable information.
Based on these discussions, the team documented many key findings. These findings
are those that have potential applicability to U.S. needs in ITS and winter
operations. The findings are presented in five topic areas associated with winter
maintenance operations, followed by two topic areas associated with motorist
information and education.
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WINTER MAINTENANCE EQUIPMENT
Advanced winter maintenance equipment continues to be developed and evaluated
in Japan and Europe. Some equipment has advanced to the implementation stage.
While several projects to evaluate winter maintenance equipment are under way
in the United States, no agency has taken the lead in supporting and encouraging
research on equipment as in other countries. Snow- and ice-control equipment
sensors used in Japan and various European countries generally are available
and used in the United States (i.e., automated controls, radar, GPS, etc.).
Advanced snow- and ice-control equipment and sensors under evaluation in Japan
and Europe fall into one of the three categories described below.
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ADVANCED MAINTENANCE EQUIPMENT
Two advances of note are in this category:
- Modified snow plow vehicle design with cab-over truck engine and double
front axles. This design allows for efficient high-speed snow-removal operations.
The cab-over engine configuration provides the operator with an unobstructed
forward view of the roadway and helps keep snow blown over the top of the
front plow from accumulating on the windscreen.
- Modified plow designs with automated down pressure control and floating
wheel. This design automatically controls the down pressure applied to the
plow blade during snow and ice removal.
Automated Vehicle Location and Navigation Systems
Three advances of note are in this category:
- Millimeter wave radar sensor. This sensor can be mounted on the front of
vehicles such as snowplows to detect obstacles in the roadway during low-visibility
conditions, such as blowing snow and fog.
- Edge-of-pavement sensors. These light-emitting delineators (LEDs) are used
to indicate the pavement edge to motorists during low-visibility conditions
from heavy snowfall and blowing snow. The LEDs, installed at specific intervals
along the roadway, flash to provide motorists with a visualization of the
road alignment. The brightness of the illumination is adjusted according to
background light, so that the brightness during clear weather is less than
that during snow storms. The brightness is also reduced at night. On divided
roadways, the LEDs are installed in the center strip and are orange. On two-lane
roads, the LEDs use green illuminating elements and are installed at the roadside.
- AVL units. An AVL unit produced in Italy is combined with GPS and appropriate
software to provide chemical spreaders with enhanced capability. This capability
includes automated, preprogrammed chemical application rate variation and
automated tracking and billing for dispensed snow- and ice-control materials.
A mobile weather station mounted on the truck also can be connected to the
AVL/GPS system to automatically report to a maintenance facility the road
surface temperature, air temperature, relative humidity, and dew point along
Vehicle-Mounted Performance-Monitoring Systems
Three advances of note are in this category:
- Road surface condition sensor. These sensors indicate wintertime pavement
surface conditions, such as icy or snow-covered.
- Salinity indicator sensor. Prototype devices to measure the salinity content
of liquid and slush on the road surface are under development by two Japanese
companies. The concepts employed use spectral analysis of refractive light
measurements and electrical conductivity measurements. These approaches complement
the chemical detection devices under development in Sweden for the past four
- Ground view sensor. These sensors have been developed to identify eight
different wintertime road surface conditions and eventually will be used to
automatically adjust spreader chemical applications.
Other key findings in this topic include the following:
- Japan has been working over the past 10 years on methods to make mechanical
measurements of friction on snow- and ice-covered pavements. Friction measurements
under wintertime pavement conditions now are made for research purposes only
and are not released to the public. Japan is moving away from mechanical friction
measurements and is exploring a number of indirect measurement methods. Officials
believe that mechanical measurements of friction cannot be used to make operational
decisions. Some European presentations and discussions appear to support this
- A number of human factor improvements have been incorporated in the design
of sensors and controls used on Japanese snow- and ice-control equipment,
but all of the improvements appear to parallel those under consideration in
both Europe and the United States.
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MEASURING AND COMMUNICATING WINTER ROAD CONDITIONS
Japan relies heavily on frequent visual observations of winter road conditions
by patrols to verify conditions detected by an extensive road weather information
systems (RWIS) sensor network. Data coming from roadway and atmospheric sensors
in Japan are used as secondary information in decisions on winter maintenance
operations, traffic control, chemical application treatments, and information
disseminated to the public. Other key findings in this topic area include the
- Significant advances continue to be made in Japan and Europe on developing
improved communication systems and protocols used between RWIS sensors and
operations centers. This work is part of an ITS effort to use road weather
information systems not only for winter road management, but also for traffic
information and control.
- In Japan, RWIS data, video surveillance of mountain passes, and weather
information are monitored on a continual basis during developing adverse winter
road conditions. Also, road surface conditions on expressways are monitored
by road patrols at least six times a day before, during, and after a winter
- In Japan, RWIS sensor data and observational data of road surface conditions
are sent to maintenance headquarters for the decision-making process. A Road
Web Markup Language (RWML) has been developed based on next-generation eXtensible
Markup Language (XML). In the RWML system, road-related information is grouped
into four categories: road information, weather information, disaster information,
and regional information. RWML enables road weather information to be distributed
easily on the Internet to PCs in road administration offices and maintenance
- No data communication exists between the Japanese winter maintenance vehicles
and the operations centers.
- Road condition information such as road surface condition, road closure,
disaster prevention information, and weather information is issued by each
road administrator. Information such as traffic restrictions is issued by
the prefecture police.
- For avalanche-prone areas, patrolling criteria have been established on
the basis of weather data at the time past avalanches occurred. No sensing
equipment is used to determine avalanche danger. Particularly dangerous sections
are designated as special traffic control sections. These sections are closed
when avalanches are predicted.
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COORDINATED USE OF WEATHER FORECAST DATA
Road weather data in many countries are collected centrally and combined with
meteorological forecast data to provide guidance to local road maintenance and
traffic control authorities. Many European countries have not yet achieved full
data sharing between their RWIS sites and their national meteorological agencies
but they are working toward that end. In Japan, road weather data are provided
only to local private meteorological forecast companies. Also, Japan has no
direct sharing of road weather condition information with other transportation
modes or with agencies outside the highway agency's jurisdiction. Outside agencies,
however, can obtain road weather information via the Internet or get e-mails
by special request. More key findings in this topic area include the following:
- The Japan Meteorological Agency (JMA) provides global and regional atmospheric
forecasts down to a 20-kilometer grid. Private meteorological companies such
as the Japanese Weather Association (JWA) use this output to drive higherresolution
atmospheric models. For example, JWA runs models at 10-kilometer, 5-kilometer,
and 1-kilometer resolutions.
- JMA also provides weather advisories and warnings, while private meteorological
firms like JWA provide specific road forecasts and disseminate specific weather
information to the public and various agencies.
- JMA has a program to certify forecasters at private meteorological companies.
- Japanese road administrators appear to have established long-standing relationships
with specific providers of road weather forecasts. These private meteorological
firms appear to operate under sole-source arrangements.
- Private meteorological companies in Japan develop and operate road surface
temperature forecast models. Japan uses thermal mapping and heat budget modeling
approaches in its road surface temperature forecasts. Japan has a high density
of RWIS stations on the expressways (about one set of sensor sites every 10
- Japan has installed many automatic snowfall rate and snow depth sensors
that report the data in real time to control centers.
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USE OF WINTER MAINTENANCE DECISION SUPPORT SYSTEMS
In the United States, the term maintenance decision support system (MDSS) is
used to describe a management system designed to gather, assemble, and organize
information on highway conditions, winter storm conditions, and winter maintenance
resources to help maintenance engineers and supervisors make effective decisions
on staffing, equipment, and chemical use in supporting winter maintenance operations.
Both European countries and Japan are developing MDSS, portions of which are
undergoing field-testing and evaluation in preparation for implementation. The
U.S. contact with foreign efforts is slight, and efforts by the United States
and other countries to develop MDSS would be enhanced by closer contact. More
specific findings in this area are highlighted below:
- The Hokkaido Regional Development Bureau (HRDB) is developing MDSS to integrate
JMA weather forecasts with RWIS sensor data to provide appropriate road weather
information to the road administrator, road patrols, and maintenance garages
via Web-based access. This information also includes pavement temperature
forecasts derived from an algorithm developed by HRDB. The pavement temperature
algorithm appears to be as sophisticated as European ones, but no data were
presented to verify the accuracy of the model.
- JWA has developed MDSS for site-specific forecasts. The meteorological information
system (MICOS) developed by JWA provides weather forecast information to all
Japan Highway Public Corporation offices through dedicated terminals for road
weather management. The weather forecast information received by the road
administrators appears to be more detailed and site specific than provided
in U.S. National Weather Service forecasts. The pavement temperature and condition
forecast provided by MICOS depends on manual observations and subjective judgment.
No data were available to verify the accuracy of the system. General weather
information, as opposed to forecast information, is provided to the public
by MICOS via a Web site and mobile I-mode phones.
- Sapporo has used MDSS with data from more than 50 snowfall sensor sites
around the city. These sites do not contain road surface condition sensors.
The sensor data plus snowfall precipitation forecasts are used by maintenance
forces to decide when to pretreat certain roads with chemical application.
Limited data from the operation of the system indicate the city achieved a
7.3 percent reduction in instances of inappropriate chemical application.
These instances include those when chemicals would have been applied but were
not needed, and those when no chemicals were applied but were needed.
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PERFORMANCE EVALUATION OF WINTER MAINTENANCE OPERATIONS
Many European countries are moving toward privatization of winter maintenance
operations. The relationships between the national agencies and contractors
appear to be more partnerships than sponsor-client relationships. The contractual
relationships force a clear definition of wintertime service levels expected
for the various road systems and lead to a method of evaluating performance
of winter maintenance operations. These methods of performance evaluation can
be valuable to winter maintenance organizations even if European countries do
not privatize their operations.
The United States appears to have higher winter maintenance service standards
and expectations for given highway classifications than many foreign countries.
This is true from the perspective of both the road maintenance agency and the
driving public. More specific findings in this area are highlighted below:
- The Japan Highway Public Corporation has developed a national maintenance
manual and is developing regional manuals. The HRDB also has developed a winter
road surface maintenance guideline. The documents describe recommended levels
of service during wintertime conditions. The HRDB guideline includes road
management goals for various highway facilities defined by combinations of
average daily traffic volume and area type. The management goals are defined
in terms of five classes of road surface conditions. Charts relate the classifications
of road surface conditions to ranges of friction coefficients determined by
research. The performance evaluation of winter maintenance operations in Hokkaido
is based on a visual inspection of road surface conditions by patrolling inspectors.
- The Cost 344 project, a European initiative, is developing a description
of best practices for a large number of transportation topics, including measurements
and performance evaluations of winter maintenance activities.
- A number of European countries have developed their own measures of performance
for winter maintenance operations, but no universally accepted performance
measures are apparent.
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WINTER TRAVELER INFORMATION
Considerable effort has been made in Hokkaido to provide wintertime travelers
with information on weather and driving conditions. This information is available
by various means both before and during travel through an extensive advanced
traveler information system (ATIS). Winter road conditions are available through
hardware and wireless access to various Internet Web sites via PCs and I-mode
(Internet-accessible) cellular phones. The development of RWML has enabled road
weather information to be distributed over the Internet. Standardization of
RWML sensor data and road weather information provided to the public is under
development in Japan as part of its ITS applications. Other specific key findings
include the following:
- Cellular telephone deployment of third-generation (broadband) services is
advanced in Japan with more than 60 million mobile Web users. For a small
monthly subscription fee, the I-mode phone provides the user with Web-browsing
capability that includes graphics, pictures, and text information.
- The pervasiveness of wireless communications in Japan in general, and in
Hokkaido in particular, has allowed for convenient distribution of urban traveler
information. Researchers from CERI, HRDC, and the Hokkaido Branch Office of
the Japan Weather Association ran an ITS experiment in the Sapporo metropolitan
area in January and February 2001 as part of the Smart Sapporo Snow Info Experiment.
The purpose of the experiment was to examine the effectiveness of using the
latest communication technology to improve traffic flow during expected winter
weather events. In the experiment, forecasted snowfall and winter road conditions
were provided to commuters over mobile phones to help them choose various
transportation modes. The results of a survey showed that 68 percent found
the information useful and 71 percent changed commuting patterns based on
the information provided. The results of the experiment were presented at
the 2002 PIARC Conference in Sapporo.
- Road weather information also is shared with the public through extensive
use of variable message signs, road information boards, highway advisory radio
(HAR), kiosk terminals, and vehicle information and communications systems
(VICS). In-vehicle navigation deployment is advanced in Japan, with both original
equipment manufacturer and after-market devices in use. Web-based ATIS is
accessible in some vehicles, but it is not clear how many of the 8 million
invehicle navigation systems in Japan contain this function.
- The Hokkaido Regional Development Bureau, through its road information Web
site "Northern Road Navi," provides photographic images of and road
weather information on three major mountain passes and the Hidaka expressway.
The Web site also displays weather information. The road information center
of the Hokkaido Regional Development Bureau provides weather information on
its Web site. The Northern Road Navi site provides winter driving guidance
and addresses of related organizations, which also provide winter road information
through the I-mode phone.
- The speed limit on the expressways can be changed during wintertime and
other hazardous driving conditions through the use of variable speed limit
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DRIVER EDUCATION FOR WINTER CONDITIONS
Driver education is taken seriously in Japan and is considered more of a social
responsibility than in the United States. Special driver programs are offered
in Hokkaido for wintertime driving conditions. A winter condition driving course
is being developed in Hokkaido for students enrolled in driver training during
milder times of the year. Through its law enforcement branch, the Prefecture
Government develops the training content and bears the cost for publicly offered
driver education courses. The Prefecture Traffic Safety Association and the
Japan Automobile Federation provide the instructors. Both agencies are the primary
sources for publicly available driver education. Private and professional driver
education programs also exist. Other positive attributes of driver education
in Japan include the following:
- A road information center at a Hokkaido Regional Development Bureau rest
area contains a variety of winter driving educational tools. These include
four fully functional driving simulators to demonstrate driving on three different
winter roads. The simulators feature an interactive 12-question driving test.
Other educational tools include numerous posters and graphical displays of
driving and safety topics located throughout the center, including the restrooms.
- Winter driving information is also available for motorists on the Web and
at strategically located kiosks.
- The Japanese government encourages motorists to use modern snow tires through
winter safety programs. These tires, which use a soft rubber compound and
a porous tread surface, provide superior traction on ice and snow. In the
United States, the tires are marketed primarily to sports car owners.
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