TOward future-Oriented Road Surface Monitoring

ACTUS

Ministry of Land, Infrastructure,
Transport and Tourism New
Technology Information System

NETIS

Registration No：KK-210066-A

Wireless IRI Measuring System【Advanced Compact Telecommunication Unwiredｰaccelerometer System】

The Simple, Convenient, and Accurate IRI measurement☆Simply press Start and Stop to take IRI measurements☆Easy to install, even on passenger vehicles☆Enjoy more accurate monitoring with a structure based solely on
IRI principles☆Quickly evaluate road surfaces with real-time monitoring☆Obtain positional information even in tunnels and other placesWhere no satellite signals are received

ACTUS (a simple IRI measurement system)
・The International Roughness Index (IRI) was proposed in 1986 by the World Bank as a metricfor linking pavement performance to motorist comfort.
・Japan has required the use of IRI to evaluate the longitudinal roughness of road surfaces
since the February 2013 publishing of the Sotenken jisshi yoryo (an) hoso hen (TheImplementation guideline on general inspections(proposed)for pavement).
ACTUS is a simple IRI measurement system that makes it possible to obtain data about roadsurfaces from regular vehicles wirelessly and while in motion from sensors installed on thevehicles. We can expect this technology to enable data acquisition at high frequencies,
improve economic efficiency and workability, shorten work schedules, and limit negative
impacts on the global environment.

Remarks①ACTUS was jointly developed by the Kitami Institute of Technology, Tokyo University of Agriculture, PROFICT LAB Co., Ltd., Kotobuki
Engineering Co., Ltd., and NEWJEC Inc.
②ACTUS was part of an event for matching needs to technology seeds hosted by the Kinki Regional Development Bureau of the Ministry ofLand, Infrastructure, Transport and Tourism.
③An industry-academia consortium was launched for the Mobile ProfiloMeter (MPM) pilot project.

T Oward future-Oriented Road Surface Monitoring◆Key Features●Acceleration sensors mounted on sprung mass and on unsprang mass of vehicle senddata wirelessly to the main unit (no need to connect the sensors to the interior)●Obtains positional information from GPS and vehicle speed pulses●Sensors extract vehicle speed pulses and relay them to the main unit, making it possible
to obtain positional information inside tunnels and other places where no satellite signals
are received● Enables real-time monitoring from computers by combining road surface data withpositional information●Plots measurements on maps and drawings◆System configuration (Installation locations)

GPSantenna

Data transmitted from the sensors to
the main unit over a wireless network(Zigbee)

Installation location of lower sensor

Installation location of upper sensor

Main unit* Laptop or tablet (separate preparationrequired)* Acceleration sensors can source theirelectric power from dry batteries or byconnecting to the vehicle battery.

ACTUS main unit
・Built-in gyrosensor
・Built-in wireless module(IEEE802.15.4: Zigbee)
・Built-in GPS module (GV-87evaluation kit)

Acceleration sensors

ACTUS main unit
(with built-in gyrosensor)

An acceleration sensor(5-cm opening, 2 cm thick)*If requested, we install and calibrate the equipment (consultation required).

・Built-in wireless module (IEEE802.15.4:Zigbee)
・Acceleration sensor ADXL345 (triaxial)
Frequency: 800 Hz

TOward future-Oriented Road Surface Monitoring◆Measurement principle（transfer function method）
Quarter-Car (QC)
Simulation

Data acquisition
Data acquisition

Filtering

IRI output

IRI calculation

Denoting

Sprung mass

Transferfunction

LUT

Unsprung mass

*It calculates IRI with consideration for vibration
characteristic of the survey vehicle.
*Patent No. 4220929 (Road surface evenness
measuring device)◆Performance
Demonstrates Class-2 performance as described in the Pavement Survey/Test Method Manual (2019 version).
Class
1
2

IRI is calculated based on QC simulations after measuring longitudinal roughness with a level or the likeMeasurement

Laser displacement sensor

IRI is calculated based on QC simulations after measuring longitudinal roughness with a laser displacement Road surface survey vehicle
sensor
IRI is calculated with sprung/unsprung mass accelerometers in the course of transfer function
ACTUS
correction based on IRI principles (QC simulation)

Accelerometers mounted on sprung
Mass and unsprang mass

3

Method of application

IRI calculation method

Method of measuring surface roughness

Rod and Level measurement

Response-type road roughness meterAn arbitrary roughness index based on acceleration is measured and converted to IRI using a correlation
equation
Physical sensations and visualconfirmation by surveyors riding IRI is presumed and quantified based on ride experience and visual inspection on patrol carsin patrol cars or the like4

Smartphone, etc.
Physical sensations,visual confirmation◆Quality of measurement

12.00
10.00
8.00
6.00
4.00
2.00
0.00

IRI/100m（National Route 24 outbound) (Comparison with road surface survey vehicle)

ACTUS
路面性状車
Road

34.50
34.90
35.30
35.70
36.10
36.50
36.90
37.30
37.70
38.10
38.50
38.90
39.30
39.70
40.10
40.50
40.90
41.30
41.70
42.10
42.50
42.90
43.30
43.70
44.10
44.50
44.90
45.30
45.7046.70
47.10
47.50

IRI(MM/M)

ACTUS was part of an event for matching needs to technology seeds hosted by the Kinki Regional Development
Bureau of the Ministry of Land, Infrastructure, Transport and Tourism in 2020, where it was compared to the roadsurface survey vehicle used in regular road surface inspections, and performed favorably in terms of economic
efficiency, work processes, quality of the final results, safety, and workability.

surfacesurveyvehicle

Distance marker●Computer screen for measurements
Displays positional information, speed IRI,
time, and more

●IRI measurement error for ACTUS and theroad surface survey vehicle

ACTUS and the road surface survey vehicle
in simultaneous operation for the comparison

TypeEquipment

Mean IRI/100 m

Mean speed

ErrorInbound

ACTUS

2.13

39.6km/h

0.99Road surface survey vehicle

2.15-

-

ACTUS

2.17

43.7km/h

0.96Road surface survey vehicle

2.27--OutboundT Oward future-Oriented Road Surface Monitoring◆Options・Plotting IRI measurements on maps：⇒The system uses GIS to plot measurements on maps for identification of damaged section.

Damagedsection ①Outboundlane

Damagedsection ②

Outboundlane

Damagedsection ③

Outboundlane

Damagedsection ④

Outboundlane

Inboundlane◆Product specification
Measurement ranges

Speed rage: 20 to 120 km/h ,Public roads, Operating temperature range: -20 to +85°C

System requirements

OS: Windows 8/10 (64-bit), Memory: At least 4 GB
Dry batteries
Three AA batteries (Battery life: Approximately 20 hours/Type: Alkaline)
Power cable that connects to vehicle battery
Vehicle battery
Main measuring unit, acceleration sensors (2), external battery box, power cable for connecting tovehicle battery, USB cable, point recording device, vehicle speed signal cable, GPS antenna, CDROM (driver), instruction manual

Sensor power source
Equipment and accessories◆Using action cameras to verify the condition of road surfaces
・ Installing an action camera (e.g. GoPro) separate from the system and taking simultaneous
measurements makes it possible to verify the consistency of ACTUS results with the condition ofroad surfaces.
Cracks in thepavement

Equipment

IRI/10m

IRI/100m

ACTUS

5.49

3.65

Rutting

Bridge joint

Photograph of the condition of the road surface◆Contact for inquiriesKitami Institute of Technology,
University-launched Venture Company
PROFICT LAB Co., Ltd.
Technology in harmony with Nature and People

NE

JEC

Camera position

Tokyo University ofAgriculture
NEWJEC Inc.
Osaka Head Office: 2-3-20 Honjo-higashi,Kita-ku, Osaka City
06-6374-4031 (Road Group)

Kinki Branch Office: 14-25
Naniwa-cho, Kita-ku, Osaka City
06-6374-4003 (Main)