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Skid Resistance History with Focus on European Activities
Vägytefriktionens historia i ett europeiskt perspektiv
By Dr. Ulf Sandberg
Swedish National Road and Transport Research Institute (VTI)
TRB 93rd Annual Meeting, Session 717 Quality Friction Measurements, January 14, 2014
Adapted for the Seminar ”Friktion på sommarvägar”, Arlanda, Sweden, 27 May 2014
[email protected]
Transportation Research Board,
January 12-16, 2014
Tidsepoker i vägytefriktionens historia
Hästepoken (före 1920)
Dåliga och hala vägytor (sten, grus), men stoppsträcka inte intressant. Folk och hästar halkar.
Motoriseringsepoken (ca 1920-1950)
Stoppsträckan börjar bli intressant, men bra mätinstrument inte tillgängliga
Kunskaps- och mätinstrumentepoken (ca 1945-1975)
Friktionsrelaterade olyckor börjar bli ett erkänt problem; både på vägar och flygfält. Kunskaperna
utvecklas -- teorier, rapporter, böcker. Intensiv utveckling av metoder och mätinstrument
Mätnings- och standardiseringsepoken (ca 1970-1990)
De nya kunskaperna och mätutrustningarna används flitigt för kartläggningar. Intern. standarder
börjar utvecklas
Harmoniseringsepoken (ca 1985 – nutid)
Insågs att utvecklingen på mätsidan varit för spretig – hade blivit ”vilda västern”: Jämförbarhet
mellan metoder och mätutrustningar mkt dålig. Åskilliga internationella projekt för att jämföra och
harmonisera mätresultat. Försök att skapa helhetsmått (PIARC 1992-94, IFI, CEN, EFI, m fl)
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The horse era
Roman roads, made of stones or
marble, were often very slippery.
This might have been a problem
in warfare for fast troop
transportation, but also for
transportation in daily life.
Romans sometimes put sandals on the hooves of
hourses, “hipposandals”, for various reasons; one of
which was to obtain better slip resistance. That type of
sandal had spines to provide better grip.
Source: Balkels (2009), The Western European Loess Belt -Agrarian History, 5300 BC – 1000 AD, Springer Science+Business Media
The horse era
In the 19th century it was common to
add anti-slip measures to horseshoes;
so-called calks or caulkins (broddar).
Primary use was to prevent slipping on
paving stones.
Source: Max G Lay (1992): Ways of the World, Rutgers
Univ Press (picture from Wikimedia Commons)
The rate of traffic accidents per pavement area were higher for horse traffic in the
19th century than for automobile traffic in modern times. A calculation indicated
one horse fall per year for each 150 square meters of pavement (corresponds to
each 20 m of street if width is 7.5 m).
Source: Max G Lay (1992): Ways of the World, Rutgers Univ Press
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The horse era - Wood block (träkubb) pavements
A major urban pavement type in Europe (first used in Russia), USA and Australia in
the late 19th and early 20th centuries
“The chief merit of a rectangular block pavement is its quietness; and its chief
defects are its slipperiness …..”
Source: I O Baker (1910): A Treatise on Roads and Pavements, John Wiley & Sons
“PREVENTION OF
SLIPPERINESS: During wet
and frosty weather, it will be
frequently necessary to spread
a light coating of sand over the
pavement in order to prevent it
from becoming slippery”
Source: Text-Book on Highway
Engineering, 1913
Picture from the museum of the Swedish Transport Administration
The horse era - measurements
In late 19th century, the quality of pavement friction was measured by counting
miles traveled by horse over different types of cobblestone pavement before an
accident occurred.
They classified slipperiness by falls on the knees and haunches (höfter), complete
falls, and those of other unspecified types. Available data from 1873 and 1885
reveals the slipperiness of each type of pavement in England and America, resp.
American data quantifies different types of falls according to types of pavement—
asphalt, granite, wood—while the English data quantifies falls according to weather
conditions on the same type of pavements.
Source:
Tom Yager, Pavement Friction
Workshop, Texas, 2 May 2012
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The motorization era (1920-1950):
problem
With increasing vehicle speed (from approx. 30 up to approx. 70 km/h), braking
and stopping distances are becoming increasingly important
The safety problem gradually becoming recognized, but only in areas with intense
motorized traffic and busy airports, and not with high priority
The motorization era:
emerging knowledge
Measurement method:
Braking on ice, measure braking distance
Pictures from the VTI archieves
Measurement method:
Apply brakes on towed truck, measure force
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Measurement results
from Report 10 (1927)
Coefficient of friction
as a function of speed
Left:
for low inflation tires
Right:
for high inflation tires
The motorization era:
emerging knowledge
Measurement method:
Lock brakes, measure braking distance
A few results:
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The motorization era: emerging knowledge
Measurement method:
Lock brakes, measure braking distance and speed, calculate friction coefficient
One automobile and two trucks used
Pavement friction
in vehicle traffic
By Dr R Schenk,
Tech Univ of Berlin
(publ. 1928)
In his report, Dr
Schenk mentions
several studies in
the 19th century !
The motorization era:
methods and equipment
Common test by simply applying the brakes of a vehicle until they block the tires
Example 1: Roadway friction tested by placing a lunch box on the passenger seat
and noting whether or not it stayed there. The driver accelerates up to 30 mph
and slams on the brakes, locking all 4 tires momentarily. If the lunch box falls off
the seat, the tire/pavement friction is deemed acceptable; if the lunch
box remains, remedial treatment is required
Source: Tom Yager, Pavement Friction Workshop, Texas, 2 May 2012
Example 2: The so-called Tapley Meter from the UK
was used worldwide to measure deceleration
Source of picture: The Detroit News pictorial, 1928
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The motorization era:
methods and equipment
A small fleet of motorcycles and side-car, with angled wheel and mechanical
linkage to transfer frictional forces from tire to chart recorder were developed and
used in the early 1930’s in the U.K.
Source: Peter Roe and Louise Caudwell, 2008
The motorization era: methods and equipment
Swiss equipment used in 1934
Source: Peter Maurer, AIT, Austria, 2012
Darmstädter Reibungsmesser with towing car in 1936
(Friction meter from Darmstadt in Germany)
Source: Peter Maurer, AIT, Austria, 2012
Sideway force coeff. (SFC) measurement by
2-wheel trailer in the UK in 1938, used at up to
60 mph (97 km/h)
Source: Leaflet “SCRIM” from TRL Ltd 2008
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The knowledge and equipment development era
(1945-1975): problems
With increasing vehicle speeds (from approx. 70 up to approx. 120 km/h), braking
and stopping distances are becoming a high-priority problem
Hydroplaning appearing as a major problem
The skid resistance problem becoming nation-wide and internationally recognized
Jet airplane flight operations: higher landing speeds give increased stopping issues
The knowledge and equipment development era:
advancing knowledge
Selection of important documents
Hartwig W. Kummer, Wolfgang E. Meyer (1960): Rubber and Tire Friction
Pennsylvania State University, College of Engineering and Architecture, 1960
Hartwig W. Kummer, Wolfgang E. Meyer (1963): The Penn State Road Friction
Tester, Department of Mechanical Engineering, the Pennsylvania State University
Kummer, HW (1966): Unified theory of rubber and tyre friction, Engineering
research bulletin B-94, College of Engineering, Pennsylvania State University,
University Park, PA, USA.
H. W. Kummer, David Lee White, W. E. Meyer (1967): Exploratory field study of
aggregate-skid resistance effectiveness, Report 315, Pennsylvania State
University, Automotive Safety Research Program, Dept. of Mechanical Engineering
State of the Art of Skid Resistance Research (1968), HRB Special Report 95
R. Schonfeld (1970): Skid numbers from stereo-photographs, DoH Ontario, Canada
Desmond F. Moore (1975): The friction of pneumatic tyres. Elsevier Science
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The knowledge and equipment development era:
methods and equipment
Laboratory and stationary field methods
Picture from http://www.bgs.ac.uk
Polished stone value (PSV)
Developed in the UK in the 1940’s
Became UK spec + requirement in 1976
Portable Skid-Resistance Tester, a.k.a. British
Pendulum Meter (BPM)
Developed in the UK in the 1960’s (published 1964 by
Giles, Sabey, Cardew at TRL)
Wehner-Schulze test
Developed at Tech Univ of Berlin, Germany around 1960
Testing friction of drilled road cores or lab slabs, after
simulated wear by tire
Picture from TRL PPR-144 (2006)
The knowledge and equipment development era:
methods and equipment
Laboratory and stationary field methods (texture and drainage)
Mean Texture Depth (MTD),
a.k.a. Sand patch method
Developed in the UK in the 1940’s
Became a UK spec and requirement in 1976
The (Water) Outflow method
Developed in the 1960’s (origin unknown to this author)
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The first designated skid resistance measuring equipment in
Sweden: Skiddometer BV-1 from 1949
Mr Kullberg at the Swedish Road Institute (later VTI) developed the skiddometer principle. With his
first Skiddometer, BV-1, Mr. Kullberg showed in 1949 that on good summer roads the maximum
friction for automobile tires occurs at 17 % slip. The advantage of the Skiddometer method is that
80-85% of braked energy can be fed back to other wheels as a propelling force
Picture from the VTI archieves
The knowledge and equipment development era:
methods and equipment
Continued:
Various skiddometers were successively developed with lower tire loads. Trailer BV11 uses 105 kg and can easily be towed by a regular car.
BV-11 was then integrated into a car. SAAB developed the SAAB Surface Friction
Tester, SFT. A fifth wheel, the friction measuring wheel, was installed in the rear of a
SAAB car model 99, becoming operational in 1969. Tire load 140 kg, slip 12 %.
Source: Gunnar Antvik ”History of friction measurements at airports”, ASFT, 1997.
The SFT is currently in use at >300 airports
The Mu-Meter was developed around 1960 in the U.K.
and is the world’s best-selling continuous skid resistance
meter (> 1000 units)
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The knowledge and equipment development era:
methods and equipment
Stuttgarter Reibungsmesser (SRM) (The Stuttgart
Friction Meter), version 1957/58, with towing truck
and watertank. The first SRM was built 1950.
High-speed (up to 160 km/h) skid resistance meter
at the Road Research Laboratory (now TRL Ltd),
around 1955
The Stradograph, from France, measuring
sideway force coefficient, in the early 1950’s
Source: Peter Maurer, ”Von der Idee einer realitätsnahen
Fahrbahngriffigkeitsmessung bis hin zur Realisierung 53 Jahre
Griffigkeitsmessungen in Österreich”, 10. Symposium
Reifen und Fahrwerk 25.11.2012 (Maurer worked at AIT, Austria)
The knowledge and equipment development era:
methods and equipment
The SCRIM (Sideway-Force Coefficient Routine Investigation Machine) was developed in the
late 1960’s by TRL in the U.K.
The SCRIM is nowadays (in various versions) one of the most widespread equipment for
measuring road pavement skid resistance
Prototype SCRIM 1968
Source: SCRIM leaflet from TRL Ltd (2008)
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The monitoring and standardization era (1970-1990):
new and improved equipment
The PIARC reference tires, intended mainly for skid resistance measurements,
became available in the 1970’s
Still in extensive use
The monitoring and standardization era (1970-1990):
new and improved equipment
The BV-12 from VTI, Sweden, can measure practically every kind of skid resistance
Introduced 1974
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The monitoring and standardization era:
new and improved equipment
Stuttgarter Reibungsmesser further
improved
Picture from website of IVT at ETH in Zurich, Switzerland
Belgian Odoliograph from early 1970’s
Picture from PowerPoint presentation by BRRC in Belgium
The GripTester was developed around 1988
in the U.K. and is the world’s second (?)
best-selling continuous skid resistance meter
Picture from brochure on the GripTester website
The monitoring and standardization era:
new and improved equipment
ASTM E-274 K J Law Trailer utilized also in Europe by some organizations
Picture from PowerPoint presentation about Klaruw downloaded from www.ciht.org.uk
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The monitoring and standardization era:
methods and equipment
Laboratory for testing hydroplaning on a drum facility at
BASt in Germany
The monitoring and standardization era:
measurement standards
Direct methods:
ISO/TR 8349:1986
Road vehicles -- Measurement of road surface friction
(Later replaced by ISO 8349:2002)
Work in CEN (European Committee for Standardization) initiated in 1989 in TC 227
(Road Materials) and its WG 5 (surface characteristics) in 1992
Indirect methods:
Work in ISO re. volumetric patch method and texture measurement started at the
end of the 1980’s
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The monitoring and standardization era:
monitoring and policies
Example from the U.K.:
PSV requirements for aggregates used on trunk roads were established in 1976
Standard for in-service skid resistance of trunk roads
was introduced in 1988, based on SCRIM testing
A corresponding ”Good Practice Guide” is
(nowadays) used by some local road authorites
Source: Roe, PG & Caudwell, L (2008): ”Skid Resistance Policy in the UK – where did it come from and
where is it going”, INTERNATIONAL SAFER ROADS CONFERENCE, Cheltenham, UK
The Harmonization era (1990 - present time):
Raised interest in Europe (and USA) for harmonization of friction and texture
methods in the late 1980’s, for example:
• Many types of equipment and methods implemented, measurement results not
comparable; e.g. test of 5 north European devices gave poor correlation
• Mobile macrotexture measurement becoming possible and implemented in RST,
ARAN (possibly an indicator of high-speed skid resistance)
• Descornet & Sandberg playing with laser texture profiles for correlation with skid
resistance
• Exchange of staff (guest researchers): Wambold (PSU) vs Sandberg (VTI)
• Sandberg performing project in coop with PSU in PA, ARRB in Australia and Univ
of Christchurch in NZ, comparing skid resistance measurements with ASTM trailer,
SCRIM and Mu-Meter, relating them to macrotexture spectra (sponsor = STU)
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The Harmonization era:
The PIARC International Experiment
PIARC Technical Committee on Surface Characteristics, becoming interested in
harmonization in the late 1980’s, from 1991 chaired by J J Henry of PSU
• A huge PIARC experiment was undertaken by the PIARC Technical Committee on
Surface Characteristics after the 1988 World Congress in Brussels
• Formally announced at the XIX World Road Congress in Marrakesh in 1991
• The full scale experiment was conducted in September and October of 1992
• Final report presented at the XX World Road Congress in Montreal in 1995
The PIARC International Experiment (1992-1995)
37 friction and 14 texture measuring equipment, 54 test sites (pavements)
Picture from the final report
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The Harmonization era:
International harmonization efforts after the
PIARC International Experiment
Annual NASA workshops and experiments at Wallops Island, VA, 1992-2008
ASTM E 1960-98 on the IFI published in 1998
CEN defined in 1998 its own IFI: the EFI (later SRI); by CEN Technical
Committee 227, Working Group 5: Surface characteristics (CEN/TC 227/WG 5)
Several new standards in ISO, ASTM and CEN related to texture and friction
HERMES (Harmonization of European Routine and research Measuring
Equipment for Skid Resistance) – FEHRL research project 2000-2006, further
testing the EFI and IFI concepts
TyroSafe – EU Coordination Action project 2008-2010
ROSANNE – Pre-normative EU research project 2013-2016
CEN/TC 227/WG 5 Technical Specifications
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The Harmonization era: State-of-the-Art Equipment
New Skiddometer (1995) by VTI (BV-14) intended exclusively for testing on winter roads
Fixed slip
Source: Leif Sjögren,
VTI, Sweden
The Harmonization era: State-of-the-Art Equipment
Indoor test facility in climatic chamber at VTI in Sweden, using moving road sections
Fixed slip
Source: VTI archieves,
Linköping, Sweden
Picture from VTI
PIARC smooth tire,
sideway force measured (at 20o angle)
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The Harmonization era: State-of-the-Art Equipment
New Odoliograph MK4, built in Belgium by BRRC
(Seems to be a fusion of the old Odoliograph and the SCRIM)
Picture from PPT Presentation by BRRC
”Building of new Odoliograph concept by
BRRC – The Odoliograph MK4”
PIARC smooth tire,
sideway force measured (at 20o angle)
The Harmonization era: State-of-the-Art Equipment
SCRIM vehicles and many other skid resistance measuring devices have been
supplemented with laser profilometer equipment for measurement of texture
and with GPS; some also with video cameras
Picture from WDM website about
SCRIM and SCRIMTEX equipment
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The Harmonization era: State-of-the-Art Equipment
German SCRIM, owned by BASt
Picture from PPT Presentation by BRRC
”Building of new Odoliograph concept by
BRRC – The Odoliograph MK4”
Source: Picture from K Scharnigg, BASt
Source: Peter Maurer, ”Von der Idee einer realitätsnahen Fahrbahngriffigkeitsmessung bis hin zur
Realisierung 53 Jahre Griffigkeitsmessungen in Österreich”, 10. Symposium Reifen und Fahrwerk
25.11.2012 (Maurer worked at AIT, Austria)
The Harmonization era: State-of-the-Art Equipment
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The Harmonization era:
Harmonization attempt: TyroSafe project 2008-2010
The ”Metro Map” of TyroSafe towards harmonization and a common scale:
ROSANNE
EU project
• ROSANNE - ROlling resistance, Skid resistance, ANd Noise
Emission measurement standards for road surfaces
• Project started 2013, duration: 3 years
• Budget: 3 million EUR
• Partners: AIT (Austria), DRD (Denmark), TRL (UK), VTI (Sweden),
BASt (Germany), IFSTTAR (France), BRRC (Belgium), TUG
(Poland), ZAG (Slovenia), FEHRL (Belgium), DIN (Germany)
• Extensive comparison of skid resistance measuring equipment
made in Nantes, France, 12-23 May 2014
28.05.2014
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Acknowledgements
The author would like to thank the following researchers for their assistance in
finding documents and pictures related to skid resistance measurement history:
Louise Caudwell, Highways Agency, London, U.K.
Karen Scharnigg, Federal Highway Research Institute (BASt), Bergisch Gladbach, Germany
Peter Maurer, Austrian Institute of Technology (AIT), Vienna, Austria (passed away in 2013)
Roland Spielhofer, Austrian Institute of Technology (AIT), Vienna, Austria
Leif Sjögren, Peter Andrén and Ulla-Kaisa Knutsson, VTI, Sweden
Pictures are by the author, unless otherwise stated
[email protected]
The End
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