Department for Transport, Energy & Infrastructure Business Management Systemsa

Department for Transport, Energy & Infrastructure Business Management Systemsa

Department for Transport, Energy & Infrastructure Business Management SystemSA -

Technical and Professional Services SectionPavements & Structures Section Business Management System

Materials GroupAsset Technology Operations

Procedure - Laboratories

Determination of Road Surface Texture Using a WDM TM2 Device


Revision: 1.40Date: May 2006Sept 02Page 1 of 14







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Transport SA

Quality Management System


Department of Planning, Transport & Infrastructure

Field Services Section

Technical Services Group


Determination of Road Surface Texture Using a WDM TM2 Device


Revision: 1.8Date: May 2012Page 1 of 4

Technical Services7August9

Determination of Road Surface Texture Using a WDM TM2 Device


This procedure describes themethod outlines the processdure to be followed in the determination of road surface texture friction characteristics (skid testing) using a WDM TM2 ProfilerGriptester. preparation, effecting and reporting the results of a Griptester survey.

The procedures to be followed shall be as described in this procedure and the Users ManualOperations and Maintenance manuals of the Griptester. There will be referrals to the manuals (in particular the Operations Manuals). They shall be read in conjunction with this procedure.

For calibration intervals refer to Procedure TSA-MAT-CP001, Appendix C.


Manufacturers Users ManualOperations Manual, WDM Bristol UKFindlay Irvine, 20011995.


Manufacturers Maintenance Manual, Findlay Irvine, 1996.

‘Characterisation of pavement texture by use of surface profiles-Part 1: Determination of mean profile depth, ISO 13473-1

:1997 Surface Friction of Pavements: Test method for measurement of surface skid resistance using the GripTester braked wheel fixed slip device, BS 7941-2.

Management of the Calibration System,TSA-MAT-CP001.

Standard Specification for a size 10 x 4-5 Smooth – Tread Test Tire, ASTM E1844


  • Accelerometer. A device for measuring the vertical acceleration while the test equipment is in operation. The accelerometer is mounted directly over the laser sensor.
  • Texture. The device measures macro-texture of the road surface. Macro-texture is the visual texture observed when examining the broad stone-binder matrix. Technically, it is defined as the characteristic deviation of a pavement surface from the true planar surface within the range of 0.5 and 50mm
  • Distance Calibration. To accurately operate and use the TM2 it is necessary to calibrate the linear measuring apparatus so the length of any test site can be accurately known and so texture variations readily logged.
  • Check mat. A preformed rubber mat used for the check calibration of the TM2 each time it is to be used.
  • MPD. Mean Profile Depth.

RMSTD. Root Mean Squared Texture DepthSkid resistance. That property of the road surface which limits relative movement between a vehicle tyre contact area and the road.

Slip resistance: The property of the trafficked surface to maintain the adhesion of a pedestrian sole.

Frictional force: The tangential force generated between the vehicle tyre and the trafficked surface

Braked wheel friction tester: An apparatus that can be moved over the test surface at a known, steady speed that included a test wheel, a system for braking the test wheel and instrumentation for measuring the resulting friction between the test tyre and test surface.

Fixed slip: A braking system that forces the test wheel to roll at a fixed reduction of the normal speed of the drive wheels.

GripTester: A braked fixed slip device friction tester capable of being manually pushed or towed up to the speed limit.

Load: The dynamic instantaneous vertical force acting on the test wheel.

Drag: The dynamic instantaneous horizontal force acting on the test wheel.

Instantaneous: Drag divided by load.

GripNumber: The mean of a number of instantaneous readings over a defined length.

GripLength: The defined length over which the GripNumber is produced.

Water deposition system: System for depositing a given amount of water in front of the test tyre so that it then passes between the tyre and the surface being measured.

Rate of water deposition: Rate at which water is deposited on the surface to be measured in front of the test tyre.

Theoretical film thickness: Thickness of the water film that would exist between a test tyre with smooth tread and the surface being measured if this surface had zero texture depth.

Routine skid resistance testing: Measurement of the skid resistance of a surface in standardised test conditions, which normally include a defined rate of water deposition.

  • Operational Skid resistance testing: measurement of the skid resistance of a surface in response to an operational need and in whatever conditions exist at the time of the test.As detailed in the references.



TM2 Texture Profiler.Griptester and ancillary equipment.
Metered standpipe., W water bladder and delivery hoses. The water flow rate shall be measured to the nearest 0.1l/min
Lap top Ccomputer.

4.1Temperature measuring device 0 – 1000C accurate to +10C
Safety equipment.
Backup vehicle (when required.)


Check Mat Water

Smooth tread test wheel manufactured by Findlay Irvine (A Series) and to ASTM E1844. The rubber formulation is designed not to require a temperature correction when being used in a test. Operating pressure is 20+1 psi.Nil.

  • Apparatus
  • TM2 mTexture Profiler
  • Safety Equipment
  • Computer
  • Materials
  • Checkmat


5.1The procedure has been developed from the Users Manual and ISO/CD 13473Operating and Maintenance Manuals of the Manufacturer as has the Standard BS 7941-2. As the procedurestandard makes frequent references to the same manuals it has been treated as a primarysecondary reference in this instance.

5.15.2The TM2 ProfilerGriptester is a precision surface profile (texture)friction tester whichmeasurement device tester, which is may be towed or pushed by hand. The device utilises a laser to measure the profile of the road surface over which it is traversing.principle of operation is the simultaneous measurement, using strain gauge sensors, of drag and load on a single wheel of 254mm diameter skidding at just under 15% of the rolling speed (a gearing ratio of 27:32 between the test and drive wheels achieves this slip). The coefficient of friction (drag/load) is displayed on a meter mounted on the Griptester and transmitted to a data collection computer.

Survey This data is stored in the internal data collector which can then downloaded to a desk top computer for processing.collection computer analyses and displays the data in The system can be a variety of ways. While the survey is being carried out, it may be interrogated at any time to provide a spot check on the texturefriction readings and the distance from the beginning of the current section. Events such as bridges, bends, junctions and changes of surface may be entered and appropriately labelled.

When the survey is finished, the results can be displayed on the data collection computer’s screen , either in the form of a summary giving the average friction reading for each section , or in the form of a trace. The data may be transferred to any IBM compatible personal computer, where it can be scanned, the events edited and a report produced.

Texture measurementsHighway friction testing should be carried out when the road is dry as moisture can influence the results by interfering with the light signals from the laser being used in the process. , but with a film of water (usually with a nominal thickness of 0.25mm) being deposited under the measuring wheel. When towed the Griptester operates at 50kph with the water being carried in the towing vehicle.

The device operates at a walking pace up to 5 k/h. In the pushedmode, operating at 5kph, the Griptester carries its own water tanks. The speed of operation is calculated by on board sensors on the GripTester and is shown on the computer screen when under test.

6.06.PRELIMINARY TO SURVEYPreliminary to Survey

6.1.1Prior to commencement of a survey, before leaving base, the appendedRefer to the checklistsshall be followed. The same applies for checklists before commencement of a survey (on site) and at the completion of work (at base)for further instructions. Form Form 1TP351-1. out a preliminary equipment check calibration before departure.

Using the check mat verify the texture measurement of the device. Refer 4.1.5.

Check that all batteries have been charged. Clause 4.1, Quick Check, Operation Manual. Should a full calibration be necessary then follow the requirements in clause 4.2 Full Check, Operations Manual.

Check that the test tyre for compliance as its condition is critical to the test (20 psi +10%).

If the tyre needs to be changed then follow the procedure as in the Operations Manual clause 4.1, which includes requirements covering the towing tyres.

7.07.Surveyand load necessary equipment prior to departure from the Materials Section.SURVEY on at the work sitearea, carry out “on site” check of equipment.

7.1.2Set up the TM2 ProfilerGripTester for either the pushed or towed mode. iThis includinges the settings on the computer and tyre pressures. GripTester with regard to data collection, the software to be used and physical layout. The settings on the GripTester dictate the data collection rates as detailed in operations manual and BS7941-2.

7.1.3If being towed connect it to the appropriate towing hitch to suit the area to be tested.

5.4Prepare the computer and equipment for a survey run. Follow the instructions as listed in the software .for the equipment.

7.1.4Prepare the computer and equipment for a survey run, either towed or pushed Clause 2 Preparing for a survey, Operations Manual. Follow the instructions as listed in the Users Manualsoftware Clause 3 Data collection and processing, Operations Manual. device is not to be used in temperatures in excess of 50 degrees C.

Measure the required temperatures ( to 1.00 C) and measure and set the tyre pressures. The temperature of the water to be used is to be between 5 and 250C .

Turn on the water to give the required film flow when thickness of 0.25 mm (Operations Manual Appendix 1 ). ready.

7.1.6Commence the survey, taking into account the prevailing traffic conditions and that and any traffic control systems are in place. Refer 4.0.backup vehicle being used is in the correct position.

7.1.7Activate the survey on the laptop computer when at the area to be tested.

7.1.8Monitor the progress of the survey on the computer screen and mark appropriate events as they occur. Maintain a steady the speed as required for either a towed (+ 2k/h) or a (+ 1k/h) pushed survey. Advise the vehicle driver as to speed maintained over the course of the survey.

7.1.9At the end of the survey, tap “End” on the computer screen press ESC on the laptop computer to cease data collection. Stop the vehicles in a safe position and turn off the water flow. The survey data results may now be viewed on the computer screen. Refer 4.1.4

NOTE: If returning to the start of the survey for another run, turn the water flow on to prevent wear and overheating of the measuring tyre. If the survey has been over a considerable distance, return to the start of the next run with the Griptester stored in the vehicle.

7.1.10.On return to base unload, check and store all equipment. Report the usage of the TM2 Profiler Griptester tyre (distance). Place the equipment and computer and Griptester onbatteriesy on charge.


8.1The resulting data from the survey may be analysed on the dedicated computer using the supplied software or down loaded to an IBM compatible personal computer for analysis, Clause 6.03, Downloading Data to a Desktop PCata collection and processing, Operations Manual. The client shall be supplied with a copy of the test report. Any interpretation of data or comments relative to the results shall be presented in a separate Materials Technology Report.where it may be scanned, the events edited and a report produced.

Accuracy of reporting. Average, and Standard Deviation (2 decimal places), Coefficient of Variation % (Integer). Sensors measuring the texturedrag and load are accurate (three decimal places) enabling the reporting of textureGrip nNumbers to 0.01, refer Users Manual Maintenance Manual Clauses 5.0 Data Format 2.1.3 and ..

8.1.1 operating ed in the towed mode the sampling rate is 100 samples per 100mm and 10 100 mm samples are averaged to give a 1 m answer. Where testing will exceed 50 m then reading a averaged into 50 m lots. 2 PPR (pulses per revolution) resulting in one sample per 10m and while in the pushed mode the sampling rate is 20 PPR resulting a sample for each 1m. (Other sampling rates and ‘GripLengths’ as designated in the references are for alternative test regimes and software systems not in use by TSA) Data is reported in as a Mean Profile Depth or as a Root Mean Square Texture Depth.

8.1.3On finalising the report, store the accumulated data on the TSADPTTEI network. required use the Microsoft Processing Package Excel to produce a graphical plot reflecting the skid resistance results relative to the TSADPTTEI maintenance markers for that section of roadThe report is to follow the format as required for Mate.

9.09.MAINTENANCE rials Technology reports. Use the templates provided in Excel for processing of the data. The recommended intervention level is to be included in any graphical reports, and to be placed in the body of the report.

See the manual for instructions regarding maintenance. In particular refer to Appendices C and D.


TSA-MAT-TP351-1344 form (Check List)

TSA-MAT-TP351-2344 form (Survey Report)


The uncertainty of measurement has been determined as + 5.0% of the test result, at a confidence limit of 95% with a nominal coverage factor of 2, when calculated in accordance with the accreditation requirements as detailed in AS/ISO 17025.



File Location: Q:/Quality Management


Materials Technology Section


Department of Planning,for Transport , Energy & Infrastructure

19 Bridge Rd Walkley Heights (08) 8260 0230, PO Box 1533 WalkervilleAdelaide SA 50081

MaterialsTechnical Services Group

Procedure – LaboratoriesTRANSPORT SA

Materials Technology SectionAsset Technology TAPS 19 Bridge Road Walkley Heights (08) 8260 0230

PO Box 82 Enfield Plaza SA 5085

19 Bridge Road, Walkley Heights, 5098




Preliminary Check List


/ Carry out “Quick Calibration Check” . Users ManualOperations Manual ClauseSection 4.1.5



Ensure all necessary safety equipment is carried



Load the Texture Profiler and computerLoad water bladder and fill with water



Load the test mat for check calibrationsLock & check necessary safety equipment



Users Manuals Standpipe, keys & delivery hoses



Tyre PumpPumps (air & water)



Traffic Control systems“A” frame for towing operation



Check that all batteries have been chargedHandle & water tanks for pushing operation



Calibration kit



Computer (including connecting cables)



Cable for electric water pump



Operations & Maintenance manuals



Spare tyres






Backup vehicle (if required)

On Site Preparation Check List

1 / Carry outPlace necessary safety signagecontrols, etc
2 / Carry out “Quick Check”
3 / Assemble the Texture Profiler Fill water bladder (if required)
4 / Set up computer following on board software Assemble Griptester
5 / Complete calibration checkSet up computer following on board software

Return to Base

1 / Unload all equipment
2 / Check and clean all equipment
3 / Place the equipment and computer on charge
4 / Transfer all data to secure database
5 / Record the test wheel distance usage
6 / Return vehicle to its storage site

Form MAT-TP351-1, Revn.1.4769

Department of Planning, Transport & Infrastructure

19 Bridge Rd Walkley Heights (08) 8260 0230, PO Box 1533 Adelaide SA 5001

Technical Services Group


Department for Transport, Energy & Infrastructure

19 Bridge Rd Walkley Heights (08) 8260 0230, PO Box 1 Walkerville SA 5081

MaterialsTechnical Services Group

Procedure – Laboratories


Materials Technology SectionAsset Technology

19 Bridge Road, Walkley Heights, 5098

Asset Technology TAPS 19 Bridge Road Walkley Heights (08) 8260 0230

PO Box 82 Enfield Plaza SA 5085

Report: Determination of Road Surface Texture using s Surface profiler TM2Skid Resistance with the Griptester


KNET NO.#………………………….Report No. ……..

Report No. ……..

Test mode / Tow/Push
Profiler, WDM TM2Griptester / GT148240-001
Measuring systemMeasuring Tyre / Class 3B LaserA series / BS.EN 60825-11994
Pavement Location
OperatorTarget Speed
WeatherSelf-wetting film
Ambient temperature 0COperator
Surface temperature 0CWeather
Surface conditionWater temperature 0C
Run NumberSurface temperature 0C / Distance / MPD / RMSTD
1Tyre Temperature 0C
2Run Number
3Surface condition
Remarks (1) / Start: MM
Remarks (2) / End: MM
Grip Number
Standard Deviation
Coefficient of Variation %

Signatory: …………………

Date: …../ …./ ….

Processed / Database / Checked / Uploaded / Knet / Sent
Signed / ………………. / ………………. / ………… / ……… / ……… / …………
Date / ………………. / ………………. / ………… / ……… / ……… / …………

Form MAT-TP351-2, Revn.1.4Form MAT-TP351976


File Location: Q:/Quality Management


Transport SA

Quality Management System