zMessages from Departments and Centers of NILIM
For more efficient use of existing road stock

Photo– Key lies in accumulating and using data–
SATO Hiroshi, Director
Road Department

1. A historic turning point
Japan’s social infrastructure development isundergoing a historic paradigm shift, and the road
sector is no exception. The systems and environments
involving roads are changing enormously; earmarked
funding for roads has been converted to generalfunding, budgets vastly reduced, the Road Structure
Ordinance devolved to regulations, expressway tollmeasures revised, subsidies converted to grants, and soon. Essentially, the fundamental role of a road is auniversal one that transcends time and space. Whileremaining cognizant of this fact, the issues to beresolved will also of course change, in line withsocio-economic conditions and changes in public
opinion, the development of science and technology,etc.; policies and the R&D that support them must also
adapt to the new era. Amid harsh limiting conditions,creative ideas in various organizations and aspects havebecome even more important, and it is surely vital that
we apply reliable technology to support the efficient
implementation of policy issues, in particular.
Amid these recent changes to limiting conditions andpolicy needs, “effective use and appropriate
maintenance of existing stock” could be cited as one
major issue. And the key to resolving this issue is“continuously and efficiently accumulating, updating
and analyzing data”. This paper will introduce some of
the initiatives for R&D in the Road Department, in linewith this perspective.
2. Integrated analysis of road traffic data
When carrying out measures to reduce traffic
congestion or manage traffic demand as means ofmaking effective use of existing stock, it is difficult toachieve this with road traffic censuses held only once
every five years, and even then only on one typical day.
Locations need to be selected and countermeasures
proposedafter
comprehensively
ascertaining,
accumulating and analyzing hourly fluctuating traffic
volumes and traveling speeds for the whole country’s
trunk roads. To this end, we are pursuing the following
research with a view to obtaining, accumulating,calibrating, supplementing, and finally using various
traffic data such as OD traffic volume, cross-sectionaltraffic volume and traveling speeds.
1) Efficient methods of obtaining traffic data
- Techniques for estimating traffic fluctuation over awide area using a traffic volume constant observation
system- Techniques for using probe data and other ITS data toobtain traveling speed data, etc.
2) Methods of standardizing and accumulating traffic
data- Methods of standardizing positional data, data
headings, etc., and methods of electronic delivery
3) Techniques for calibrating and supplementing trafficdata- Methods of supplementing data in unobservedsections and time zones- Techniques of reverse-estimating OD traffic volumeusing traffic volume data4) Methods of computing evaluation indices, etc., using
traffic data
- Congestion-related indices (aggregation of losthours, etc.)- Indices related to time constancy (time reliability,etc.)- Indices related to traffic demand (vehicle kilometers
traveled by type of vehicle, etc.)
Our aim is to be able to evaluate the effects andpriority levels of individual locations subject tocongestion measures by using detailed and highly
reliable congestion-related indices, achieve qualitativeevaluation from the user’s viewpoint by using time
constancy indices, and ascertain traffic demand
fluctuation on national trunk roads in real time by using
traffic demand-related indices.
3. Improving traffic safety
In 2009, traffic accidents resulted in 4,914 deaths, thenumber falling below 5,000 for the first time in 57years. However, this is still an unacceptable figure, andthe new administration has set the target of halving
road deaths by 2018 and achieving the safest roadtraffic environment in the world. Improving traffic
safety is synonymous with improving the quality ofexisting stock, and is one of the most importantpolicies.
On trunk roads, priority measures are effective insectors with a high rate of accident occurrence. As withcongestion countermeasures, we will need to selectlocations for implementing measures, propose
measures, evaluate their effects, etc., while
continuously accumulating data on traffic accidents
and the implementation of safety measures. To this end,
we are pursuing the following research aimed at
upgrading techniques for analyzing the current status ofaccidents, efficiently obtaining data on accidents andhazards, and analyzing the effects of countermeasures,among others.

zMessages from Departments and Centers of NILIM

1) Expanding techniques for ascertaining the current
status of hazards and upgrading analytical techniques- Techniques for analyzing and ascertaining thecurrent status by driving experiments involving
eye-mark recorders and video data analyses- Methods of using private-sector drive recorderinformation to glean the present status of hazards2) Upgrading techniques for selecting safety measures- Techniques for building a safety measure database,improving accuracy when evaluating the effects ofsafety measures, and evaluating composite measures- Establishing techniques for factor analysis based on
driving experiments, etc., in locations where thecause of accidents is difficult to ascertain
We aim to tackle research that will not only enhancethe effects of traffic safety policies amid severebudgetary constraints, but will also promote
understanding and trust in various regions and in public
opinion. This will be done by making it possible toselect effective countermeasure locations based on thepresent status of each location, as well as increasing thereliability of countermeasure effects and making it
possible to ascertain and express these quantitatively.
4. Towards “preventive conservation” and “totaloptimum”
Japan, as a mountainous archipelago, has a road
network supported by a vast complex of roadstructures, including more than 150,000 bridges and9,000 tunnels. There have been repeated reports ofserious deterioration and damage to these structures inrecent years. This is the result of aging, compounded byharsh natural conditions not often found in otherdeveloped nations (earthquakes, typhoons, torrential
rains, heavy snow, tidal waves, etc.). Establishingconservation measures for these structures is therefore
an important task.
To prevent accidents and terminal damage due to thedeterioration of structures, we need to carry out
accurate inspections, diagnosis, etc., and accumulatedata, correctly analyze and ascertain the nature of thedeterioration or damage based on the accumulated data,and carry out appropriate repair, reinforcement or
preventive conservation measures based on the resultsof highly reliable prognosis. Roads also have tofunction as networks, and when assessing structures orimplementing countermeasures, we need not only tooptimize in units of individual structures, but also tooptimize the content of countermeasures, their timing
and sequences, etc., for whole groups of structures.
This could also be seen as an important perspective interms of achieving the maximum investment effectamid budgetary and other constraints.
To this end, we are pursuing the following research
aimed at gaining an accurate grasp of the status ofindividual structures, more correctly evaluating theirperformance, and evaluating whole groups ofstructures with a view to the total optimum.
1) Techniques for accurately ascertaining the status ofstructures- Techniques for optimizing the system of inspections- Techniques for prognosis on the status ofdeterioration, etc., of structures
2) Techniques for more correctly evaluating theperformance of structures- Techniques for estimating the load resistance
performance of structures subject to deterioration anddamage- Techniques for estimating the effects of repair andreinforcement
3) Techniques for evaluating whole groups of roadstructures- Techniques for quantitatively evaluating themaintenance status of groups of road structures
Our aim is to achieve a balance between reducing
lifecycle cost and improving the reliability of roadservices. We will do so by supporting a shift from post
facto conservation after carrying out remedial
countermeasures for individual structures, to strategic
preventive conservation based on the latest data andhigh-precision prognosis.
5. The role of “roads” as universal entities
transcending time and space
As it happens, the city of Nara is now celebrating the1,300th anniversary of the establishment of the Heijo
capital there. Roads were part of the core infrastructure
supporting the birth of the nation at Nara and its
subsequent glory. The “Takeuchi Kaido” was a
regional trunk road that could be called the very first
National Route in Japan. “Taishi Michi” was an accessroad that supported the project to build the Ikaruga
Palace. “Kami-tsu-Michi, Naka-tsu-Michi andShimo-tsu-Michi” (Upper, Middle and Lower Roads)
were urban planning roads to assist area demarcation,and “Yamanobe-no-Michi” (Mountainside Road) was adomestic road that linked settlements on the shores ofLake Yamato. These ancient Nara roads provide
conclusive evidence that the fundamental roles andvaluable nature fulfilled by “roads” are universal ones
that will always transcend time and space. Encouragedby this irrefutable evidence, we would like to tackle
research and development with a view to providing arobust response to all kinds of change.