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The FY2010 Road Traffic Census
Results of the General Traffic VolumeSurveys (Overview)

Traffic Engineering Division, Road Department
UESAKA Katsumi (PhD, (Eng.)), (Head), MONMA Toshiyuki (PhD, (Eng.)), (SeniorResearcher),
MATSUMOTO Shunsuke (Research Engineer),
HASHIMOTO Hiroyoshi (Research Engineer),MIZUKI Tomohide (Guest Research Engineer)(Keywords) Road Traffic Census, traffic volume survey, travel speed survey, traffic survey reference segment
1. Introduction
The Road Traffic Census is conducted roughly
once every five years to ascertain actual conditions
surrounding Japan’s roads and road traffic. Given
that FY2010 was a census year, NILIM took steps
to further develop and bring greater efficiency to thecensus’s surveys. These steps are described inNILIM’s 2011 report. The results of the general
traffic volume surveys (traffic volume survey, travel
speed survey, and road conditions survey) werecompiled and then jointly presented to the media by
MLIT’s Road Bureau and NILIM in September
2011. The following gives an overview of theseresults together with the results of subsequentstudies.
2. Overview of survey results
Figure 1 shows changes in average traffic volume.
On urban expressways, traffic volume decreased by
6.4% compared to FY2005 (2.6% decrease on allroads) due to traffic dispersal and other effects
generated by network development. On the other
hand, on national expressways, average traffic
volume increased by 7.4% due to toll-free
expressway trials and other reasons, while traffic
volume on ordinary roads decreased by 5.8% andthat on prefectural roads, etc., decreased by 4.3%.
These outcomes suggest that traffic is shifting tonational expressways.
(vehicles/（台/24h）24 hrs)

80,00072,61972,41968,30370,00063,56359,523 △6.4％

Next, Figure 2 shows results obtained from acomparison of the travel times of congested andnon-congested periods using newly introduced probe
data from ordinary vehicles. The figure shows that,while there are large fluctuations in speed caused bytemporal variations in traffic volume on expressways,
speed differences caused by congestion on ordinary
roads are small, remaining below several kilometers
per hour. It is surmised that, in the case of ordinary
roads, the dominant factor is the effect of traffic
signals rather than changes in traffic volume.
Additionally, differences in travel speed (servicelevel) due to road classification are small on ordinary
roads, indicating that stratification of road functions
has not progressed. Thus, it will be necessary toreinforce the travel functions of ordinary roads in thefuture.
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0

Congestedperiods (7:00 – 9:00 A.M. and混雑時（7,8時台、17,18時台）
5:00 – 7:00 P.M.)
Non-congested
period (9:00 A.M. – 5:00 P.M.)
非混雑時（9時～16時台）(km/h)

National
expressway

Urban
Ordinary road
expressway(MLITadministered)Ordinaryroad(other)Major
regionalroad

Ordinary
prefectural
road

Road total

Figure 2. Comparison of travel speeds ofcongested and non-congested periods (DID)

60,00050,00040,00030,00020,00010,000027,601

11,28529,09327,823

11,965

12,222

7,870

7,394

4,847

4,542
2004
H62007H9National expressway
高速自動車国道

25,593
12,133

8,040
4,988
2009
H11
Urban
expressway
都市高速道路8,041

11,435 △5.8％
7,829
△2.6％

5,010

4,796

2005
H17Ordinaryroad
一般国道

27,481 ＋7.4％

Prefecturalroad, etc.
都道府県道等△4.3％

2010
H22Total
合計

Figure 1. Changes in average traffic volume byroad classification

The improvement of survey items in the roadconditions survey has made it possible to engage infundamental study toward the rebuilding of road
spaces. This makes it easier to prepare roadtimetables aggregate survey and analysis results forindividual municipalities by introducing traffic
survey reference segments (new census segments)(see page A Road Traffic Survey Platform
Application of “Reference Road Segments andReference Intersections”). As an example, Figure 3
shows CO2 emissions per one kilometer of road
length that were calculated at the municipality levelfrom the traffic volume and travel speed surveys(Figure 3).

凡例

5.00 以上
2.00 ～ 5.00
1.00 ～ 2.00
0.50 ～ 1.00
0.25 ～ 0.50
0.25 未満(単位：ton-CO2/12h・km)（単位：ton-CO2/12h）

Figure 3.CO2 emissions per 1-km road lengths bymunicipality* Results of the FY2010 Road Traffic Census are available via
the IR website of the Road Bureau, MLIT.
http://www.mlit.go.jp/road/ir/ir-data/ir-data.html- 2 -