Messages from Departments and Centers of NILIM

Movement and outlook of dynamic traffic
management by IT
Yukihiro Tsukada
Director of Research Center for Advanced Information Technology(Keywords) ITS, Expressway, Traffic management, Fare policy, Smart IC, Information service
1.

Introduction
Expressways have been playing an important role oflogistics and mass transportation between regions asfoundation of social and economic activities. The
proportion of expressway length represents a mere 0.6%
against the total road length, but it increases to 9% oncar/kilo basis and further to 44% in terms of transportvolume of logistics. In addition, expressways fulfilled afunction as an emergency transport route and risk
management infrastructure at the time of the Great East
Japan Earthquake.
However, by comparison with foreign expressways, ourroad length per head almost equals to -√population1) andour expressway density is relatively low now.
The fatal and injury accident rate of expressways
against general roads is 1/12 of total roads and also
expressways demonstrate considerable decrease of
CO2 emission, but utilization rate of expressways is low
in comparison with foreign countries. Althoughutilization rate of expressways in Europe and the UnitedStates is about 30%, our number is only 14% showing
insufficient utilization. There are several reasons noted
such as many missing links, high expressway toll andlong distance between interchanges (IC) which is 10 km
and about twice as long as the distance in foreigncountries.
On the other hand, in order to solve traffic issues suchas ease of traffic congestion, traffic safety andenvironment protection by seeking well-balanced
utilization of expressways and general roads in eachregion, polices like reduced rate and installation of smart
IC are being implemented.
2. Present situation of traffic management ofexpressways
Expressway management utilizing IT falls into the four
general classifications, namely, information service,traffic control, fare policy and enhancement of network
access. Movement at home and abroad concerning eachpolicy shall be explained below.
(1) Traffic information service (VICS, routeguidance)
VICS that distinguishes and delivers congestion degreefrom traffic counters and speed sensors, and displays
traffic information on car navigation systems and mobile
terminals is becoming widespread. In addition, a large
scale and detailed dynamic route guidance using ITS
spots set up on expressways has started. Furthermore,
traffic information service by automakers and private

information companies is becoming a big trend together
with spread of personal terminals like smart phones, etc.
Users make a shrewd choice of time and routes, etc.
owing to such information service.
(2) Speed control (speed control and management)
Speed control is a policy that traffic controllers
recommend or force to control speed in order to keepsmooth traffic in case of congestion or an emergency(accident, abnormal climate, etc.). Active Traffic
Management : ATM) which is introduced in the U.K. andthe United States is a representative sample. ATM
controls speed in real time on the basis of traffic volumeand speed data. Especially, in case of an accident,
ordinary automobiles are allowed to run on breakdown
lane in order to keep a lane for accident handling vehicles,
thereby accident handling time has been actually reduced
significantly. Lane guidance in a sag zone enabled byresearch and development of ITS and a cruisingtechnology by ACC will be effective linkage with speedcontrol.
(3) Fare policy (road pricing, reduced rate)
In our country, a reduced rate pilot program has been
executed throughout the nation with the aim ofproblem-solving such as improvement of environment inarea along a road and ease of traffic congestion throughtraffic conversion from general roads to expressways.
Councils involved in the pilot program around thecountry have contributed to improve receptivity ofresidents through program planning and execution, andalso publicity and explanation of the outcome.
A nationwide analysis from both sides of effect ofcongestion ease and feasibility (degree of elasticity)
showed the results that (i) reduced rate was effective inthe morning and evening and late at night, especiallylate-night reduced rate made a remarkable switch ofheavy vehicles from general roads to expressways, (ii) if
an access to IC is good, degree of elasticity is high, etc.
On the basis of the results of the pilot program, variousand elastic reduced rates such as commuting reduced ratein the morning and evening using ETC and late-night
reduced rate, etc. have been executed in earnest.
In Europe and the United States, policies to ease traffic
congestion in cities and regions by application of roadpricing to toll-free roads. For example, in major
metropolitan regions in the United States, HOT lane
which charges a part of lanes using IT is prepared as atraffic congestion mitigation program. Depending on aregion, pricing and collecting method is different, adynamic road pricing that fluctuates rates based on themeasured value in order to keep the speed above a certain
level on a pay lane is recognized as the most effective
method. Further, in Europe, congestion tax charged by
ANPR in London and Stockholm and running distance
rates for heavy vehicles charged by GPS and DSRC in
EU countries such as Germany are becoming full-fledged.
In Stockholm, the congestion tax was controversial at thetime of introduction, however, as a result of its
introduction following a pilot program and a referendum,
inter-city traffic has been reduced by 24% three years
after full-scale operation and favorable rating forcongestion tax has risen to 74%. In this manner, thesecountries conducted pilot programs and flexibly
introduced a fare policy utilizing IT, and finally gained
support of residents through actual achievement to solve
traffic issues.
(4) Enhancement of network access (Smart IC)
In our country, 63 smart ICs are installed and being
operated across the country (as of April, 2013). As smart
IC deals with ETC mounted vehicles only, it has merits
such as simple tollgate installation, no collecting
personnel and finally about a half of installation cost incomparison with traditional IC. In view of the present factthat ratio of ETC utilization has reached 88% at the endof 2012, further increase of utilization volume will beassured. It has been observed that the utilization volumeof smart is affected by time crunch population and ETC
penetration, etc. and also linked to various fare policies.
For example, an exponential increase of utilization
volume has been recognized in a trial free charge as wellas adjacent IC. Utilization of smart IC has increased
significantly because of functional advancement of IC
such as full and 24hour operation, and handling of heavy
vehicles. Furthermore, features of IC such as use forsightseeing and enhancement of access to emergency
medical facilities are fully used.
3. Proposal of dynamic traffic management
Along with preparation of expressway network,
selection of plural routes has become possible and it is
becoming important to execute policy to guide traffic by
information service and fare policy. As mentioned inabove 2, IT technology is good at assisting users to takeactions wisely within a regional and limited time byproviding in real time detailed information meticulously.
In case of expressway management, it is possible toprovide meticulous services such as (i) providing in realtime information on congestion and fare, (ii) setting aproper level of fare, (iii) locating IC optimally, (iv)maintaining running environment for above a certainspeed. Moreover, it is important to link policies of (i)through (iv) with each other. The author would like topropose traffic management which incorporates dynamic
road pricing by IT composed of an integrated
combination of information service, fare policy andaccess control, and also route guidance. Specifically, theproposed method provides in real time information onwide area congestion situation and a fare corresponding
to this situation, then guide the nearest IC and show
recommended route based on such information. It isnecessary to verify cost and effect, but I believe that it ishighly probable from technical point of view.
4. Various fare policies by IT and running distance
rates 2)
In Europe and the United States, pilot programs andreview to introduce running distance rates by IT insteadof fuel tax are carried out rapidly in view of securing
revenues for social infrastructure corresponding to therapid spread of EV and fuel-efficient car. It is a toughchallenge to have this charge accepted by society
considering a sense of burden of the charge, privacy andfairness, etc. but it is sure that discussion in thosecountries will become more lively because it istechnically feasible.
In consideration of running
distance rates for heavy vehicles on main highways andactual introduction of congestion charges during peak
hours and study progress of GPS usage on general roads
for experimental running distance rates, it is highly
possible for the time being that running distance charges
will be introduced for limited type of cars within an area
including expressways and main highway network.
Although the time of introduction is unclear, I firmly
believe that EV and micro-mini mobility are generalized
and personal terminals play a great role.

[References]
1) Hitoshi IEDA: Vision – The Role of the Roads
Responding to the Falling Population Environment:‘Square root of Population×Area(national landcoefficient) hypothesis’ and ‘Interaction opportunity
hypothesis,’Dôro (Roads) Magazine March issue
2005, pp4-52) See below for the recent developments of therunning distance rates issues:
http://www.gao.gov/products/GAO-13-77