July/August
2001
International
Cooperation to Prevent Collisions at Intersections
by Cathy Frye
The United
States and Japan have joined forces in the hope of finding technology-based
solutions to reduce the high incidence of crashes at intersections.
Teaming together for the new U.S.-Japan Intelligent Transportation
Systems (ITS) Joint Research Program, both countries are exchanging
information and discussing solutions being developed, evaluated, or
implemented in their respective nations.
The ITS
Joint Research Program was initiated in November 2000 in Turin, Italy,
during the 8th Workshop on ITS in the United States and Japan. The
workshop was held in conjunction with the 7th World Congress on Intelligent
Transport. The workshop participants laid the groundwork for the future
cooperative study and agreed that their long-range research topic
will be the evaluation of the effects of infrastructure support for
intersection collision avoidance (ICA). In addition to exchanging
progress reports throughout the year, Joint Research Program participants
will hold an annual meeting to review findings.
Each
year, both countries will focus on one research subtopic for study.
The topic for 2001 is systems concepts and requirements for infrastructure
support for ICA.
In the
spirit of "two heads are better than one," both countries will take
this opportunity to look at solutions that are aimed at reducing the
number of crashes at intersections in the United States and Japan.
Because the two countries frequently take different approaches to
resolve the same problem - too many accidents occurring at intersections
- the Joint Research Program is a learning experience for all involved.
To further
advance the Joint Research Program's information exchange, Japan is
sending an engineer to the Turner-Fairbank Highway Research Center
each year on a fellowship. Having a Japanese research fellow at the
Federal Highway Administration's (FHWA's) center for research, development,
and technology helps in the day-to-day informal exchanges of information.
Both countries are excited about the potential advances in intersection
collision avoidance that could come from this cooperation.
At
the Cross Roads or in the Cross Hairs?
According to the International Road Traffic Accident Database, an
estimated 10 million traffic crashes worldwide occur each year, and
these crashes claim the lives of one-half million people. Sixty percent
of the crashes occur in the United States, and of those, 27 percent
of the crashes in the United States occur at intersections. Intersection
crashes are in a statistical dead heat with rear-end collisions, which
account for 28 percent of all crashes on U.S. roads, as the second
most common type of crash occurring on our roads. This makes intersections
"among the most dangerous locations on U.S. roads," according to FHWA's
ITS Joint Program Office.
In Japan,
intersection collision statistics are even more staggering; more than
58 percent of all traffic crashes occur at intersections. Thirty percent
of all Japanese traffic accidents involving fatalities occur at intersections,
and the majority of these fatal crashes happen at intersections without
traffic signals.
Intersections
Present Unique Problems
The crash statistics from both the United States and Japan clearly
show the dangerous nature of intersections. Intersections are far
more complicated than other roadways, such as a divided highway where
all of the traffic on each side of a median is flowing in one direction.
Since an intersection is a decision point for vehicles from multiple
directions, many variables are at play. Vehicles may need to stop,
start, yield right of way, slow, accelerate, or turn. Drivers may
purposefully ignore traffic signals - as is often the case with red-light
running - or simply misunderstand them.
Intersections
present the ideal environment for crossing-path crashes in which both
vehicles are initially traveling from either perpendicular or opposite
directions and then one vehicle cuts across the path of the other.
There are four types of crossing-path crashes:
- Straight
crossing paths (SCP).
- Right/left
turn into path (R/LTP).
- Left
turn across path - lateral direction conflict (LTAP/LD).
- Left
turn across path - opposite direction (LTAP/OD).
In addition
to vehicular crashes, pedestrian accidents in intersections are also
a problem. In the United States, 70,000 vehicle-pedestrian collisions
occur annually, and 40 percent occur in intersections. More than 45
percent of all pedestrians hit by vehicles in Japan are struck in
an intersection, and an astonishing 52 percent of these incidents
occur while the pedestrian is in the crosswalk.
The
Weak Link
Surprisingly, the cause of most crashes is not adverse road conditions,
driving under the influence, or even vehicle defects. In the human-machine
collaboration that occurs during driving, the weak link is often the
human. Driver error is the cause of 90 percent of all police-reported
car crashes in the United States.
Preliminary
study data from the ITS Joint Program Office indicate that with the
full deployment of just three Intelligent Vehicle Initiative (IVI)
systems, one in every six U.S. crashes would not occur. IVI systems
are being designed to enhance human performance and guard against
human shortfalls such as limited sight distance and reaction times
that are not fast enough to keep a crash from happening.
Emerging
Intelligent Vehicle Systems
U.S. research is looking at collision countermeasures. Initially,
these could be infrastructure-only systems that rely solely on roadside
warning devices to signal drivers. Ultimately, the emerging systems
could evolve into cooperative systems that communicate information
from the infrastructure directly to vehicles and drivers.
![Illustrations of Intersections.](images/intersections.gif) |
Figure
2- Illustrations of the types of crossing-path crashes.
|
|
For example,
a countermeasure aimed at reducing red-light running could use sensors
to identify potential traffic-signal violators by determining the
speed and the deceleration rate of each vehicle at a fixed location
before the traffic signal. Once a potential violator is detected,
a roadside warning device could display a warning with flashing lights
to "stop ahead." This infrastructure-only system might make use of
magnetic loop detectors, self-powered vehicle detectors (SPVDs), optical
sensors, or radar sensors in addition to a variable message sign -
all currently available off-the-shelf products.
With
a future cooperative system, instead of relaying a warning to the
driver through the use of a variable message sign, a warning could
be communicated directly to the potential red-light runner inside
the vehicle via a message console, an audible warning, or other sensory
warning. With refinement, cooperative systems could detect the vehicle,
determine that it is approaching the intersection too fast to stop,
and assume control so that it is stopped before potentially causing
an accident at the intersection.
Although
the potential to develop cooperative road-vehicle systems exists,
this capability is a controversial development in the evolution of
human travel. It brings with it potential liability issues in the
event of a system failure, and it requires a general change in thinking
that the human driver should always be solely in control of the vehicle.
![What is the IVI?](images/what_is_the_ivi.gif) |
Figure
3 - Goal of the U.S. Intelligent Vehicle Initiative.
|
|
Other
potential systems that may be coming off the American drawing board
include "smart stop signs." These smart stop signs, like the already
described red-light-running countermeasure, could use conventional
magnetic loop detection, optical sensors, or radar sensors to reduce
the number of crashes that occur near U.S. stop signs each year -
currently, about 79,000 crashes per year. Not only would the potential
violator be notified before missing the stop sign, but warnings could
be conveyed to drivers on adjacent approaches to the same intersection.
In this way, even drivers with the right of way would be alerted to
avoid a crash.
But the
danger of a collision at an intersection controlled by stop signs
is not just a result of a driver who fails to stop; sometimes, after
stopping, a driver fails to yield the right of way. How often have
you been at a four-way stop when one driver mistakenly took the right
of way? Poor judgment regarding right-of-way decisions adds another
362,000 collisions per year in the United States.
More
complex than identifying potential stop sign runners, stop sign "movement
assistance" to identify right-of-way priority would require algorithms
that "must model vehicle movements at the intersection based on the
results of individual driver decisions, distill opportunities for
individual vehicles to move, and then control messaging to drivers
that will effect movements with extremely high reliability," said
Bob Ferlis, team leader of the Enabling Technologies Team for FHWA's
Office of Operations Research and Development.
If just
installing a traffic signal at the intersection sounds like a simpler
solution, think again. These intersections would already have traffic
signals if they were warranted.
A similar
approach can be taken to create a countermeasure to crashes that occur
when a vehicle is making a left turn and is struck by a vehicle approaching
from the opposite direction and moving through the intersection at
a relatively high rate of speed. This countermeasure would be designed
to determine the speed and acceleration or deceleration of each vehicle
approaching the intersection from the direction that is opposite a
potential left-turning vehicle. Here, research pushes the limitations
of available technology as sensors to measure both speed and acceleration
are not yet commercially available. This is also why looking at technology
applied in other countries such as Japan may have big payoffs for
U.S. research and development efforts.
In Japan,
several intelligent vehicle innovations are already being field tested
or are currently available. In addition to intelligent cruise-control
systems that maintain a set interval between vehicles, there are several
interesting applications of collision-avoidance systems. The same
type of vehicle sensors that are used in the intelligent cruise-control
systems were employed in Japan to avoid rear-end collisions.
The Japanese
also have what they call "Stop & Go" systems, which are designed for
operating vehicles in heavy traffic congestion. Using Stop & Go, the
driver controls the accelerator, but the system controls the brakes
to maintain a safe following distance from the vehicle ahead. "It's
like a very slow-speed cruise control," said Paul Olson, ITS specialist
at FHWA's Western Resource Center in San Francisco.
The 9th
Joint U.S.-Japan Workshop on Advanced Technology in Highway Engineering
and "Smart Cruise 21 - Demo 2000," a demonstration of Japanese ITS
systems, were conducted in Tsukuba, Japan, Nov. 28 to Dec. 1, 2000.
Members of the U.S. delegation to the workshop observed the most recent
Japanese ITS developments.
The Japanese
are researching and developing other systems that rely on roadside
sensors as well as in-vehicle sensors. A system known as VICS (Vehicle
Information and Communications System) collects traffic information
and puts it on the Internet to be broadcast to complex roadside variable
message signs and to in-vehicle navigational devices. The traffic
information collected from the roadside sensors is transmitted to
in-vehicle devices using overhead-mounted infrared devices.
The communication
is two-way between the vehicle and the roadside. The roadside sensor
sends information on congestion to the vehicle, and the vehicle sends
information on vehicle speed and identity to the central computer
systems. The central computer systems use the information to detect
and predict congestion. The in-vehicle devices also receive information
over FM radio channels and the antennae for the FM part of the system
are quite distinctive.
In Japan,
in-vehicle navigation systems are very popular and about 60 percent
of the in-vehicle navigation systems are VICS-compatible. By March
2001, approximately 2.8 million automobiles in Japan were equipped
with VICS receivers, and VICS service is available in 28 of Japan's
47 prefectures (provinces) and on all Japanese expressways.
|
|
|
Figure
4 - IVI includes several different types of advanced safety systems. |
Using
Intelligent Vehicle Technology to Avoid Crashes Waiting to Happen
When one vehicle runs a red light and hits two others in an intersection,
it is a senseless human tragedy. Frequently, witnesses watch vehicles
collide as if in slow motion, but remain helpless to warn oncoming
vehicles. The U.S.-Japan ITS Joint Research Program promises to create
countermeasures to avoid many of the crashes that are just waiting
to happen. The countermeasures will assist humans in seeing the dangers
ahead, provide warnings before it's too late, or create intelligent
vehicles and roadways that will protect us from the human errors that
often lead to collisions.
Intelligent
vehicle (IV) technology can augment human senses and reflexes and
provide drivers with warnings in enough time to stay safe. Done right,
it's like having an angel on your shoulder.
Despite
all the promise of IV technology, researchers remain cautious and
highly conscious that effective warning devices will require substantive
human-centered research and experimentation to ensure that the warnings
are clear and do not provide drivers with additional distractions.
Just like cell phones, which have enhanced safety by allowing motorists
to call for emergency aid more quickly than ever before, all gadgets
placed inside the vehicle can potentially distract the driver. In-vehicle,
high-tech additions require an interesting balancing act. Is the newest
gizmo a potential lifesaver or a dangerous distraction? Alerting drivers
to unsafe situations that they cannot see or predict down the road
would be a powerful tool to reduce crash rates as long as the devices
do not provide the human brain more information than it can handle
while maintaining control of a vehicle.
To guard
against creating hazards instead of eliminating crashes, researchers
in both countries agree that human-centered considerations play a
large role in bringing emerging IV systems to market. Researchers
are also aware that it will take time for drivers to adapt to the
new high-tech systems and new rules. The specifics pertaining to designing
collision countermeasures, introducing collision-avoidance systems
on public roadways, and determining which countermeasures work best
in particular locations are all complex issues for which "two heads
[or two countries working together] are better than one." Both countries
intend to learn from each other's successes and failures.
Meet
the ITS Joint Research Program's Japanese Research Fellows |
As
part of ongoing cooperation with Japan, the Federal Highway
Administration (FHWA) has hosted for several years a research
fellow from Japan. Each year, a Japanese research fellow works
with FHWA's Office of Operations Research and Development at
the Turner-Fairbank Highway Research Center in McLean, Va. The
fellow brings to the United States a wealth of experience and
information about research activities in Japan and facilitates
cooperation on a variety of topics of mutual interest, including
support for the ITS Joint Research Program.
Kotaro
Kato, the incoming research fellow, majored in civil engineering
at Hokkaido University, where he graduated in 1985. For the
past three years, he has worked for Japan's Ministry of Land,
Infrastructure, and Transport (MLIT) and is currently deputy
director of the Road Traffic Control Division for the Road Bureau.
"The
ministry has been promoting R&D [research and development] and
the implementation of ITS systems, such as VICS [Vehicle Information
and Communications System, designed to provide traffic information],
ETC [Electronic Toll Collection System, designed to automate
toll collection], and AHS [Advanced Cruise-Assist Highway Systems,
designed to provide driving support]," he said. Kato has been
involved in many intelligent transportation systems (ITS) applications,
but he is especially proud of ETC and AHS.
"ETC
services started in the Tokyo metropolitan area in spring 2001
after several years of R&D," he said. "In my former job in the
Toll Road Section of the ministry, I was involved in having
ETC go a step further into the R&D phase.
![Shigenobu Kawasaki.](images/person_kawasaki.jpg) |
Shigenobu
Kawasaki, previous Japanese research fellow.
|
|
"As
for AHS, our efforts are bearing fruit - our proving tests,
Smart Cruise 21, which started last October in Tsukuba City,
were successful. During the proving tests session, we held Demo
2000, a four-day demonstration of AHS from Nov. 28 to Dec. 1.
About 2,400 participants experienced AHS there. I was fully
involved in these proving tests and demonstration."
While
at FHWA, Kato will be involved in exchanging information and
coordinating the joint activities of the U.S. and Japanese governments
in the ITS field.
"I
hope I can help advance the U.S.-Japan ITS Joint Research Program
for intersection collision-avoidance systems," he said.
An
avid skier who grew up in a snowy region of Japan, he sees his
fellowship as an exciting opportunity for someone who has never
lived in the United States.
"I
want to learn many things about the United States - history,
culture, and so on," he said. "I hope to broaden my views and
make good friends."
![Kotaro Kato.](images/kotaro_kato.jpg) |
Kotaro
Kato, current Japanese research fellow.
|
|
Kato
began his fellowship at FHWA in May, replacing Shigenobu Kawasaki.
During his year at FHWA, Kawasaki helped to coordinate the launching
of the ITS Joint Research Program between FHWA and MLIT. MLIT
has jurisdiction over road administration in Japan - similar
to FHWA - and it also manages national highways just as state
departments of transportation do in the United States. An important
distinction is that, unlike FHWA, MLIT is in charge of both
ITS R&D and ITS deployment in Japan.
Differences
between the two countries abound, Kawasaki said, especially
"geographic features, culture, traffic rules, and so on. Therefore,
each conclusion about intersection collision-avoidance systems
may be very different in our two countries." These differences
are precisely why he feels it is so important to continually
share information about each idea and R&D approach. The ITS
Joint Research Program is the tool that will help advance our
understanding of appropriate ITS solutions for each country.
Kawasaki
holds a master's degree in civil engineering from the Tokyo
Institute of Technology, and for 15 years, he has worked in
the Japanese Ministry of Construction, which, along with the
former Ministry of Transport and two other agencies, was integrated
into the new MLIT in January 2001.
Prior
to his fellowship at FHWA, Kawasaki was deputy director of the
Planning Division for the Road Bureau of the Ministry of Construction
in Tokyo.
"In
Japan," he explained, "a national government employee moves
from one area of the ministry to another at about two-year intervals.
At my level in the ministry, we are required to rotate through
various branch offices and research positions outside the ministry's
main office in Tokyo."
Previously
in charge of budgeting, planning, and implementing various ITS
programs for the Ministry of Construction, he was responsible
for creating a "Comprehensive Plan for ITS" in Japan and for
launching VICS in 1996.
"I
enjoyed the daily office life [in the United States] very much,
thanks to the kindness and support of many FHWA staff members,"
Kawasaki said.
While
here, he studied FHWA administrative systems, including ITS activities.
FHWA administrative systems, he said, are more highly developed
than those in Japan.
His
wife and two children, ages 7 and 11, also enjoyed their American
adventure. The Kawasakis spent much of their free time visiting
U.S. national parks.
As
a contributor to the progress of cooperation between FHWA and
MLIT, Kawasaki hopes to be able to continue to promote substantial
information exchanges about ITS activities between both countries.
Summing
up his work experience here, he said, "Although the United States
and Japan are halfway around the world from each other, I found
more similarities than differences. In particular, I found that
the national government staffs in both countries share the same
dedication and professional goals regarding ITS."
|
Reference
Robert Ferlis. Infrastructure Systems - Intersection Collision
Avoidance: Overview of Concepts, Federal Highway Administration,
Washington, D.C., March 2001.
Cathy
Frye is the founder of The Fresh Eye, a woman-owned sole proprietorship
established in 1994 to provide writing, editing, and publications
management services. She holds a degree in writing from Johns Hopkins
University and has more than 20 years of experience as a writer and
editor. She has worked on various FHWA projects in the past, including
the 1997 and 1998 Research and Technology Program Highlights
reports.
Other
Articles in this Issue:
HELP
WANTED - Meeting the Need for Tomorrow's Transportation Work Force
The
Dwight David Eisenhower Transportation Fellowship Program: Preparing
for the Future of Transportation
The
Millennium Manual Matters
QuickZone
Iowa's
Approach to Environmental Stewardship
Moveable
Barrier Solves Work-Zone Dilemma
Learning
From the Big Dig
A
Light at the End of the Tunnel
International
Cooperation to Prevent Collisions at Intersections
Pay
Attention - Buckle Up: Safe Driving Is a Full-Time Job