Available via license: CC BY 4.0
Content may be subject to copyright.
*Corresponding author. E-mail: hubert.sar@pw.edu.pl
Copyright © 2019 e Author(s). Published by VGTU Press
is is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unre-
stricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
TRANSPORT
ISSN 1648-4142 / eISSN 1648-3480
2019 Volume 34 Issue 4: 415–424
https://doi.org/10.3846/transport.2019.10426
INFLUENCE OF EXPLOITATION CONDITIONS
ON ANTI-SKID PROPERTIES OF TYRES
Janusz POKORSKI, Hubert SAR*, Andrzej REŃSKI
Institute of Vehicles, Warsaw University of Technology, Poland
Received 29 March 2017; revised 8 July 2017; accepted 24 August 2017
Abstract. Tyre-to-road adhesion plays an important role when taking into account transmission of forces between tyres
and road surface. It consequently inuences vehicle safety. Moreover, it plays a signicant role for modelling vehicle mo-
tion, which is oen applied in the development of automotive active safety systems and in trac accidents reconstruction.
Furthermore, tyre-to-road adhesion properties are dependent on many factors. One of the factors is the type of tyre– sum-
mer or winter. is is the reason why it is justied to study the anti-slip properties of summer and winter tyres. is paper
shows the method of measuring tyre-to-road adhesion coecient. It is based on a skid resistance tester SRT-4 that consists
of a special dynamometer trailer, towing vehicle and test-measuring equipment. It was designed to be applied in civil/road
engineering and further developed. As a result, the SRT-4 system automatically obtains adhesion characteristics, such as
the graph of tyre-to-road adhesion coecient as a function of wheel slip ratio and velocity characteristics of lock-up adhe-
sion coecient. Results of the study present the above mentioned characteristics for dierent types of tyres (summer, win-
ter) in dierent exploitation conditions. Dierences between presented characteristics caused by tyre type and conditions
of exploitation are shown. For example, for winter tyres we noticed that the peak value of adhesion coecient was attained
for higher values of slip ratio as compared with summer tyres.
Keywords: tyre-to-road adhesion, skid resistance tester, trac safety, accident reconstruction, active safety systems, tyre
properties, tyre wet grip index.
Notations
Variables:
m – adhesion coecient;
m0 – lock-up adhesion coecient for longitudinal slip
ratio s= 1;
mpeak – peak adhesion coecient;
w – wheel angular velocity;
w
– wheel angular deceleration;
Fz – vertical force;
W – braking force between brake pad and brake disc;
h – length on which force W is developed, i.e. between
brake pad and brake disc and thereby giving the
braking torque;
J – wheel mass moment of inertia about its rotational
axis;
r – tyre radius;
T – adhesion (friction) force;
v – longitudinal velocity of the vehicle.
Abbreviations:
ABS– Anti-lock Brake System;
ESP– Electronic Stability Program.
Introduction
Investigation of anti-slip properties of tyres is a very im-
portant issue, because the adhesion between tyre and road
surface has an impact on the active safety of an automobile
as presented by Hac and Bodie (2002), Başlamışlı (2014),
Will and Zak (2000), Nam etal. (2015), Li etal. (2012). It
also plays an important role when talking about accident
reconstruction as presented by Han (2017).
Tyre patterns and properties of rubber such as the
hardness and elasticity especially in dependence on the
temperature play a signicant role in vehicle motion sta-
bility and the vehicles ability to steer. e approach to the
416 J. Pokorski et al. Inuence of exploitation conditions on anti-skid properties of tyres
problem of interaction between tyre and road is described
by Ella etal. (2013), Skouvaklis etal. (2012), Higgins etal.
(2008), Deng etal. (2013), where indoor tests of tyres are
presented. ey give us an active insight and an extension
into further development. e main advantage of such
tests are that they are done under stable conditions and
results are repeated which is represented tribologically. An
interesting method of investigating safety of a vehicle in
curvilinear motion is described by Parczewski and Wnęk
(2015), where a physical model scaled 1:5 equipped with
all necessary sensors is presented. e advantage of this
method, contrary to a full-size vehicle, is that it does not
require a lot of space to perform road tests. Another meth-
od to solve the problem of tyre–road adhesion is by nu-
merical analysis using the nite element method applied
by Choi etal. (2012), or by using the brush model of tyre
pattern as presented by Heinrich and Klüppel (2008). In
one of the papers, Pinnington (2009) and Persson (1998)
explain a methodology of simulating the interaction be-
tween tyre and road surface characterized by dierent
structure and stochastic unevenness. All the above-men-
tioned approaches are discussed by Besdo et al. (2010).
Farroni (2016) describes the interaction between tyre and
road and also elaborates on the eect of factors such as
temperature eld. Every time numerical models applica-
tions are discussed, their parameters should be identied
through the comparison to the experiments on real object.
Another solution for tyre–road adhesion coecient
calculation is by performing road tests. Firstly, Zhao
etal. (2016) describes an approach based on road tests of
an automobile for dierent driving conditions. is way
of obtaining adhesion coecient between tyre and road
is rather an estimation and the method is therefore indi-
rect. Another indirect method of estimating tyre–road
adhesion coecient is presented by Patel et al. (2008),
where the adhesion coecient is obtained on the basis of
a braking manoeuvre. Another example is shown by Sjah-
danulirwan (1993), where only simple measurements are
needed with low number of input data to identify the tyre-
to-road adhesion. Similar approach is presented by Enisz
etal. (2015), where the adhesion coecient is obtained on
the basis of road tests of an automobile through Kalman
ltering of measured signals.
Nevertheless, a direct method of adhesion coecient
measurement is the best solution, of course, if it is avail-
able. Majority of devices applied in adhesion coecient
measurement was developed for the needs of civil engi-
neering, in particular road surface diagnostics, which
plays an important role in trac safety. is is the reason,
why these systems are usually able to obtain adhesion coef-
cient m only for a constant value of longitudinal slip ratio
s, because they are used in road surface diagnostics, for ex-
ample (Radó 1994). However, there are some exceptions,
where a full adhesion characteristic is obtained, for exam-
ple Polish SRT-4 system (Pokorski etal. 2015) and German
PETRA measuring system (Klempau 2001). However, only
SRT-4 system is able to obtain adhesion characteristic m(s)
automatically in single braking test. e full adhesion
characteristic m(s) gives more information in the context
of automotive active safety systems, especially ABS.
e dierence of anti-slip properties between summer
(normal) and winter (snow) tyres is the object of discus-
sion when to swap tyres. Very oen, it can be heard that
it should be below 7°C. e aim of the article is to check
whether such opinion is justied. Moreover, there is an-
other popular opinion that a winter tyre is made of more
elastic rubber compared to a summer tyre. e Authors of
the paper are expecting the dierences in adhesion char-
acteristics m(s), not only in the context of maximum values
of adhesion coecient, but also looking at possible dier-
ences between the values of longitudinal slip for which the
peak adhesion coecient is reached.
Investigation of wheel dynamics is rather a complex is-
sue. It is relatively simple to investigate normal reaction
forces, as presented by Makowski and Knap (2014), for the
case of a tested automobile, where these forces are meas-
ured through the measurement of suspension deection
and knowledge of its stiness. However, it is much more
complicated to perform measurements of longitudinal
tangential forces on the patch between tyre and road.
1. Description of the measurement system
e goal of the performed experiments was to show how
the various conditions inuence the tyre–road adhesion
properties. Especially, the value of the coecient of ad-
hesion for summer and winter tyres for a vehicle driv-
ing on pure asphalt or snow under various temperature
conditions were studied. e study was based on the per-
forming experiments for measuring friction force that was
developed between the tyre and the road surface while
braking. Experiment for calculating the friction force was
through a SRT-4 (skid resistance tester) measurement sys-
tem depicted in Figure 1. e system described in detail
by Pokorski etal. (2015), consists of a dynamometer trail-
er and a towing vehicle. Figure 1b presents the kinematic
schema of a dynamometer trailer.
Suitably arranged structure of the trailer and test–
measuring system makes it possible to adjust braking
torque that is acting on the wheel of a trailer (presented
additionally in Figure 2) and thus record the signals re-
quired for determining the friction force between the
wheel and the road surface.
e trailer is equipped with a longitudinal double
wishbone suspension. is type of suspension guarantees
that when the wheel is braked, then there is no inuence
of the braking torque on the value of normal reaction force
between road and wheel.
e important feature of the presented measuring sys-
tem (SRT-4) is the ability to obtain the adhesion charac-
teristic– the coecient of adhesion as a function of the
wheel longitudinal slip as a result of recording one (single)
braking of the measuring wheel on the chosen section of
the road surface. Applied European testing devices require
Transport, 2019, 34(4): 415–424 417
multiple attempts to override the test section with the slip
ratio values being changed, for example German PETRA
device (Klempau 2001). One of the aims of this study is
to present the results of the adhesion characteristics ob-
tained using the original innovative measuring system
(dynamometer trailer) for a possible comparison (but not
in this article) with traditional, time-consuming and cost-
ly methods. Another aim of the study was to present the
characteristics of adhesion (in dierent road conditions)
obtained by means of the innovative measuring set.
2. Description of the methodology used
e system presented in Figures 1 and 2 is integrated with
a data acquisition and processing system to enable auto-
matic determination of the full adhesion characteristics on
the basis of one braking attempt.
Figure 3 shows the signals that are measured during
braking test using dynamometer trailer in time domain.
Each iteration of braking lasts for approximately 2 s. e
braking torque applied to the brake disc (1) generates a
friction force between the wheel and the road surface (3)
and thereby causes a reduction in the rotational speed of
the wheels (2).
2.1. Obtaining the adhesion coecient
e adhesion coecient m represented by Equation (1)
can be summated as the ratio of the adhesion (friction)
force T and the vertical force Fz (these forces are presented
in Figure 1b):
z
T
F
m= . (1)
e static normal load of the measurement wheel (the
vertical force Fz) of the dynamometer trailer equalled dur-
ing the investigation 3.5kN. e dynamic changes of this
force varied ±5% around 3.5kN value of the static normal
load.
Figure 1. Fourth generation of skid resistance tester SRT-4:
a– a photo of towing vehicle and dynamometer trailer;
b– kinematic schema of dynamometer trailer with double
wishbone suspension
Figure 2. Single-wheel dynamometer trailer
W
T
m2
m1
a
b
a
b
a = h
rh
Fc3
Fc1
F = T
c2
v = const
a)
b)
Figure 3. Dynamometer trailer measurement signals: 1– wheel velocity; 2– braking torque;
3– wheel friction force; 4– wheel normal load
418 J. Pokorski et al. Inuence of exploitation conditions on anti-skid properties of tyres
Longitudinal slip s of the wheel while braking is de-
noted by Equation (2) and expressed in percentages:
100%
vr
s
v
− ⋅w
= ⋅ . (2)
For testing, the towing vehicle is moving at a constant
velocity and the measuring wheel of the dynamometer
trailer is braked until it locks. Moreover, it is possible to
make experiments also for wet conditions, because the
skid resistance tester is equipped with a system that pours
the water behind the measurement wheel. For the control
valves closed, it is of course possible to perform the inves-
tigation on a dry road surface or on a snowy road.
e suspension system of the trailer is based on a double
wishbone system, which minimizes the inuence of the trail-
er suspension kinematics on a longitudinal tangential force.
Adhesion coecient is measured by analysing the
rapid increase in braking force W to create wheel lock.
Equilibrium equation of the torque on a wheel that is be-
ing braked is shown by Equation (3):
Wh Tr J⋅ = ⋅ + ⋅w
. (3)
As we know that for the wheel to lockup its angular
velocity is w= 0. erefore, the dependence between brak-
ing force and friction force is represented by Equation (4):
h
TW
r
= ⋅ . (4)
e described procedure below helps to compute the
value of the adhesion coecient, which is supported by
the signal values obtained from the mounted force sensors
(Fz, T and W) in two dierent manners:
– applying friction force signal T (Equation (5)):
T
z
T
F
m= ; (5)
– by braking force W (Equation (6)):
W
z
Wh
Fr
⋅
m= ⋅
. (6)
In addition, by braking the dynamometer trailer we
analyse characteristics such as frictional force and the
rotational velocity of a wheel (for constant velocity v of a
vehicle– see Figure 1b) and thereby obtain characteristic
m(s) as the dependence between tyre-to-road adhesion and
wheel slip. ey were obtained for non-steady-state driv-
ing conditions for the time interval t1 (see the screen of the
oscilloscope in Figure 3) and for constant velocity v equal
to the velocity of the towing vehicle (Wambold etal. 1995).
Also the averaged friction force values in the time in-
terval t2 (when the wheel is completely locked) for varying
sliding velocities v of the wheel allow to make the so-called
velocity characteristics m0(v) as presented in Section 3 and
are widely used in road engineering.
2.2. Filtration of the measured signals and
the adhesion characteristics approximation
e characteristics m(s) are presented in Subsections 4.1,
4.2 and 4.3. ey were determined by:
– the application of original ltering procedures for the
friction force measurement results (curve 3 in Figure3)
and the wheel rotational speed (curve 2 in Figure3);
– the approximation of the so-obtained, non-smooth
adhesion characteristics m(s) based on one of the
three (optionally chosen by the investigator) com-
monly used formulas– Pacejka (2012), Dugo etal.
(1970), Radó (1994).
e eect of ltering the friction force and the wheel
rotational speed is shown in Figure 4.
Exemplary adhesion characteristics aer the ltration
procedure and the approximations are shown in Figure 5.
Figure 6 represents the values of m(s). Two values of
adhesion coecient are dened as follows:
–m0– lock-up adhesion coecient for the longitudinal
slip ratio s= 1;
–mpeak– peak adhesion coecient.
e adhesion characteristic is regarded here as the de-
pendence between the adhesion coecient and the wheel
slip as depicted in Figure 6.
Figure 4. e friction force T divided by the wheel normal load Fz and circumferential velocity of the wheel r⋅w aer ltration
0
10
20
30
40
50
60
70
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Time [s]
Wheel circumferential velocity [km/h]r
Чw
Friction force T divided by wheel normal load F
z
friction force (unfiltered)
friction force (filtered)
wheel velocity (unfiltered)
wheel velocity (filtered)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Transport, 2019, 34(4): 415–424 419
As already mentioned before, lock-up adhesion coef-
cient m0 is specic for road engineering, where anti-slip
properties of road surfaces are investigated. In this case,
special measurement systems are used such as dynamom-
eter trailers.
In case of automotive engineering, where active safety
of an automobile is investigated, the peak adhesion coef-
cient mpeak is taken into account, which depends on the
value of slip of the wheel. Determining two characteristic
points on the adhesion characteristic is possible based on
single braking (see also Figure 3).
e results shown in this article are the continuation of
the work presented by Pokorski etal. (2012).
2.3. e object of the research
e following tyres of size 185/65 R14 and the ination
pressure 0.22 MPa were tested:
– summer tyre of producer 1(directional tread geom-
etry;
– winter tyre of producer 1(directional tread geom-
etry);
– summer tyre of producer 2(asymmetric tread geom-
etry);
– winter tyre of producer 2(directional tread geom-
etry).
e research was performed for dierent ambient tem-
peratures of 32, 13, 2 and–15°C on a pure asphalt road
surface and additionally on snowy road surface. For test-
ing on a snowy road, the air temperature was slightly be-
low 0°C. is was done both for summer as well as winter
tyres, which were manufactured in Europe.
For the temperatures above 0°C the experiment was
performed both for wet and dry road conditions. It is im-
portant to note that the experiment was performed on
pure asphalt surfaces of Polish national roads. For sub-
zero conditions the experiments were carried out in War-
saw (Poland) on a cold and dry road. Because of the safety
of the measurement, the Authors of the study made some
investigations also on snowy road surface, but for lower
values of sliding velocities.
3. Characteristics describing m0 as a function of v
Figure 7 represents the velocity characteristics m0(v) ob-
tained by experimenting on a wet road for dierent values
of sliding velocity v (velocity of a vehicle). e velocity
characteristic represents dierent sliding velocities, so it
requires repeating the wheel braking experiments many
times (Figure 3). is characteristic also refers to one of
four tested tyres.
e vertical dynamic load of the wheel is controlled
via the force sensor (Fc3, Figure 1b) and in the presented
measurements it did not exceed 5% of the static load.
Figures 8 and 9 represent the characteristics m0(v) for
ambient temperatures 2 and 13°C while driving on a wet
road. Here, the summer as well as the winter tyres were
analysed.
e eect of ambient temperature on adhesion coef-
cient between tyre and road is small (Figure 8). In fact,
this is seen over the entire range of sliding velocities i.e.
30, 60 and 90km/h and is independent from the tyre type
(summer or winter).
Characteristically, even for the temperatures close to
0°C (Figure 9), summer tyres are characterized by higher
forces of friction as compared to winter tyres. is can be
observed irrespective of the tyre manufacturer.
e measurement results presented here can be ob-
tained using classic European measuring systems com-
monly used in road engineering. However, these sets are
not able to determine the full adhesion characteristics as
easily as the SRT-4 system (see Section 4).
Figure 5. Exemplary m(s) characteristics: a– unltered, ltered
results and one exemplary approximation; b– approximations
using dierent formulas
Figure 6. Values of m0 and mpeak based on m(s) characteristic
a)
0
0.2
0.4
0.6
0.8
1.0
Adhesion coefficient m
Slip [s]
unfiltered measurement results
filtered measurement results
approximation
v = 58 km/h
0
0.2
0.4
0.6
0.8
1.0
Rado
Dugoff
Pacejka
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
v = 58 km/h
Adhesion coefficient m
Slip [s]
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
b)
0.2
0.4
0.6
1.0
1.2
v = 60 km/h
0
Automotive engineering
Road engineering
Slip [s]
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Adhesion coefficient m
mpeak
m0
420 J. Pokorski et al. Inuence of exploitation conditions on anti-skid properties of tyres
4. Adhesion characteristics m(s) obtained
in dierent weather conditions
4.1. Adhesion characteristics m(s) for wet asphalt
road surface and ambient temperature above 0°C
Figures 10–15 show the characteristics m(s) when temper-
ature of the air rises above zero (32, 13 and 2°C).
Peak adhesion coecient is regarded as the maximum
adhesion coecient read from the curve of adhesion char-
acteristic. It was found that peak adhesion coecient in
the case of winter tyres occurs at signicantly higher slip
ratio values as compared to summer tyres (Tables 1–6).
e reason for this may be the fact that rubber of winter
tyres has a higher range of elasticity as compared to sum-
mer tyres. In addition, the values of peak adhesion coef-
cient are higher for summer tyres when considering the
temperatures above zero (32, 13 and 2°C). e adhesion
characteristics obtained for the temperatures above zero
show that the coecient m for a summer tyre is higher
compared to a winter tyre for the whole slip ratio range.
Figure 7. Exemplary velocity characteristic m0(v)
Figure 8. Velocity characteristics m0(v)
for dierent ambient temperatures
Figure 9. Velocity characteristics: comparison
of summer and winter tyres
0
0.2
0.4
0.6
0.8
1.0
Sliding velocity v [km/h]
Wet surface, T = 13 °C
Adhesion coefficient m
0
0 10 20 40 50 60 70 80 90 100 11030
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Tyre-to-road adhesion coefficient m
0
(s = 100%)
1 – road surface
temperature 13 °C
2 – road surface
temperature 2 °C
W
Wet surface
1
2
20 40 50 60 70 80 90 10030
Sliding velocity v [km/h]
1 – summer tyre
2 – winter tyre
1
2
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
Tyre-to-road adhesion coefficient m
0
(s = 100%)
20 40 50 60 70 80 90 10030
Sliding velocity v [km/h]
Wet surface, T = 2 °C
0
0.2
0.4
0.6
0.8
1.0
1.2
v = 60 km/h
Tyre producer 1:
Wet surface, T = 32 °C
Slip [s]
0 0.2 0.4 0.6 0.8 1.0
Adhesion coefficient m
1 – summer tyre
2 – winter tyre
1
2
0
0.2
0.4
0.6
0.8
1.0
1.2
Tyre producer 2:
Wet surface, T = 32 °C
Slip [s]
0 0.2 0.4 0.6 0.8 1.0
Adhesion coefficient m
v = 60 km/h
1 – summer tyre
2 – winter tyre
1
2
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
Tyre producer 1:
Wet surface, T = 13 °C
Slip [s]
0 0.2 0.4 0.6 0.8 1.0
v = 60 km/h
1 – summer tyre
2 – winter tyre
1
2
Figure 10. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 32°C, producer 1)
Figure 11. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 32°C, tyre producer2)
Figure 12. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 13°C, tyre producer1)
Transport, 2019, 34(4): 415–424 421
Table 1. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 1, wet surface, v=60km/h, T=32°C)
mpeak speak m0
Summer tyre 0.83 0.11 0.51
Winter tyre 0.81 0.21 0.48
Table 2. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 2, wet surface, v=60km/h, T=32°C)
mpeak speak m0
Summer tyre 0.91 0.11 0.50
Winter tyre 0.78 0.15 0.46
Table 3. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 1, wet surface, v=60km/h, T=13°C)
mpeak speak m0
Summer tyre 0.93 0.08 0.51
Winter tyre 0.88 0.18 0.50
Table 4. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 2, wet surface, v=60km/h, T=13°C)
mpeak speak m0
Summer tyre 1.00 0.08 0.50
Winter tyre 0.84 0.15 0.45
Table 5. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 1, wet surface, v=60km/h, T=2°C)
mpeak speak m0
Summer tyre 0.93 0.09 0.51
Winter tyre 0.88 0.19 0.50
Table 6. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 2, wet surface, v=60km/h, T=2°C)
mpeak speak m0
Summer tyre 1.00 0.10 0.49
Winter tyre 0.84 0.17 0.45
4.2. Adhesion characteristics m(s) for sub-zero
temperature and dry asphalt road surface
Due to trac safety and a risk of freezing of trailer con-
trol valves, the experiments were performed only on dry
asphalt in Warsaw (Poland).
It can be seen that for low temperatures of about–15°C,
the characteristic m(s) in case of winter tyres shows a high-
er value for the entire range of slip ratio s. It is depicted by
Figures 16 and 17, and additionally depicted in Tables 7
and 8.
In case of the winter tyre– producer 1 (Figure 16),
there can be seen the value of the peak adhesion coe-
cient, which is higher than 1.0. e reason of this is pos-
sibly the micro unevenness of the road. A tyre tread some-
how meshes with an unevenness of the road. is increases
the adhesion coecient above the value that results from
the normal load of the wheel. It needs to be highlighted
that some tyres are able to get a very high adhesion coef-
cient for optimal slip ratio. Some surfaces (for example a
sintered (calcined) bauxite) under wet conditions have a
coecient of adhesion greater than 1.2. A sintered bauxite
(Woodward, Friel 2017) is an extremely durable skid re-
sistant aggregate, which is used in high friction surfacing.
e peak adhesion coecient higher than 1.0 is also ob-
served in the work performed by Singh and Taheri (2015).
It has to be emphasized that the results shown in Fig-
ures 16 and 17 relate to the measurements on dry, clean
surfaces at negative temperatures, unlike all the previous
wet surfaces at positive temperatures.
Figure 13. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 13°C, tyre producer2)
Figure 14. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 2°C, tyre producer 1)
Figure 15. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature 2°C, tyre producer 2)
v = 60 km/h
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
Tyre producer 2:
Wet surface, T = 13 °C
Slip [s]
0 0.2 0.4 0.6 0.8
1.0
1 – summer tyre
2 – winter tyre
1
2
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
v = 60 km/h
Tyre producer 1:
Wet surface, T = 2 °C
Slip [s]
0 0.2 0.4 0.6 0.8
1.0
1
2
1 – summer tyre
2 – winter tyre
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
v = 60 km/h
Slip [s]
0 0.2 0.4 0.6 0.8
1.0
Tyre producer 2:
Wet surface, T = 2 °C
1
2
1 – summer tyre
2 – winter tyre
422 J. Pokorski et al. Inuence of exploitation conditions on anti-skid properties of tyres
Table 7. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 1, wet surface, v=60km/h, T=–15°C)
mpeak speak m0
Summer tyre 0.94 0.09 0.64
Winter tyre 1.12 0.23 0.81
Table 8. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 2, wet surface, v=60km/h, T=–15°C)
mpeak speak m0
Summer tyre 0.92 0.12 0.65
Winter tyre 0.98 0.23 0.79
4.3. Adhesion characteristics m(s) for snowy road
surface and sub-zero ambient temperature
For comparative aims, measurements of adhesion on snow
using SRT-4 system were performed.
Adhesion characteristics of investigated tyres for se-
lected attempts are presented in Figures 18 and 19, and
additionally represented by Tables 9 and 10. On the basis
of presented results, it can be stated that winter tyres are
characterized by a higher adhesion coecient on snowy
road surfaces with ambient temperature slightly below
0°C compared to summer tyres, especially in case of tyre
producer 1.
Table 9. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 1, snowy surface, v=25km/h, T=–2°C)
mpeak speak m0
Summer tyre 0.26 0.35 0.15
Winter tyre 0.48 0.30 0.25
Table 10. Dierences in slip referring to mpeak adhesion coecient
(tyre producer 2, snowy surface, v=25km/h, T=–2°C)
mpeak speak m0
Summer tyre 0.29 0.17 0.12
Winter tyre 0.37 0.23 0.20
Conclusions
e knowledge of tyre-to-road interaction is very needed
for automotive technology. On the one hand, one of the new
EU directives– Regulation (EC) No 1222/2009 (EC 2009)
requires labelling for all new tyres. Among others, the la-
bel contains the information about tyre-to-road adhesion.
It means that the basic information about tyre-to-road
adhesion is given. However, this information is targeted
mainly to the customer, which makes it useless to make a
simulation concerning the motion of a vehicle. erefore,
some further information is necessary, because the tyre-
to-road adhesion coecient depends for example on the
Figure 16. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature–15°C, tyre producer1)
Figure 17. Adhesion characteristics m(s) for summer and winter
tyres (ambient temperature–15°C, tyre producer2)
v = 60 km/h
Tyre producer 1:
Dry surface, T = –15 °C
Slip [s]
0 0.2 0.4 0.6 0.8
1.0
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
1
2
1 – summer tyre
2 – winter tyre
v = 60 km/h
Tyre producer 2:
Dry surface, T = –15 °C
Slip [s]
0 0.2 0.4 0.6 0.8
1.0
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
1 – summer tyre
2 – winter tyre
1
2
Figure 18. Adhesion characteristics m(s) for summer and winter
tyres (snowy road surface, tyre producer 1)
Figure 19. Adhesion characteristics m(s) for summer and winter
tyres (snowy road surface, tyre producer 2)
v = 25 km/h
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
Tyre producer 1:
Snow, T = –2 °C
Slip [s]
0 0.2 0.4 0.6 0.8 1.0
1
2
1 – summer tyre
2 – winter tyre
Tyre producer 2:
Snow, T = –2 °C
v = 25 km/h
Slip [s]
0 0.2 0.4 0.6 0.8 1.0
0
0.2
0.4
0.6
0.8
1.0
1.2
Adhesion coefficient m
1 – summer tyre
2 – winter tyre
1
2
Transport, 2019, 34(4): 415–424 423
longitudinal slip and the sliding velocity. Furthermore, it
strongly depends on weather conditions and road surface.
Based on thorough investigation of the tyre-to-road adhe-
sion, including dierent types of tyres (summer, winter),
we presented the results of the adhesion measurement
results. is study gives a valuable information for auto-
motive experts how tyre-to-road adhesion properties vary
according to weather conditions and a type of a tyre:
1. e innovative measuring system used in the pre-
sented research is able to determine the adhesion
characteristics m(s) on the basis of single braking test
of the measurement wheel. Comparative to some
extend European measuring devices are measuring
the adhesion properties for the xed value of slip.
e authorial soware responsible for the measure-
ment processing is obtaining the m(s) characteristics
aer automatic ltration of the measured signals.
is is the reason why the adhesion characteristics
are so smooth;
2. e research was conducted on clean asphalt road
surfaces in the range of the temperatures from–15
to +32 °C. For temperatures above zero summer
tyres are characterized by a higher coecient m0
(when a wheel is locked) as compared to winter
tyres. e same eect takes place for the tempera-
tures close to zero. Similarly, for the temperatures
above zero the peak values of the adhesion coe-
cient µpeak are higher in case of summer tyres. us,
the deterioration of the anti-slip properties is not
observed until the temperature is approximately
7°C, which is oen regarded as decisive when to
change from summer to winter tyres;
3. For extreme winter temperatures of–15 °C and
beyond, the m(s) characteristics of winter tyres are
characterized by signicantly higher value of coe-
cient m. is can be observed for the entire range of
the longitudinal slip ratio and hence the value of co-
ecient mpeak is higher for winter tyres as compared
to summer tyres. Another reason being that winter
tyres are made up of a rubber, which has a higher
value of elasticity. Certainly, it aects the function-
ing of such active safety systems such as ABS or ESP
as these systems are working closely near the maxi-
mum value of adhesion coecient mpeak;
4. Additionally, some experiments were made on snow
for ambient temperature slightly below 0°C. e ex-
periments on snow together with the investigation
for the ambient temperature–15°C and dry surface
clearly show the advantage of using winter tyres.
Additional investigations for winter conditions of snow
and ice should be performed in order to validate our meas-
urements. In addition, tyres used for summer, winter as
well as all weather conditions from several manufactures
should be further analysed for anti-slip properties.
References
Başlamışlı, S. Ç. 2014. Development of rational tyre models for vehi-
cle dynamics control design and combined vehicle state/param-
eter estimation, International Journal of Vehicle Design 65(2/3):
144–175. https://doi.org/10.1504/IJVD.2014.060766
Besdo,D.; Heimann,B.; Klüppel,M.; Kröger,M.; Wriggers,P.;
Nackenhorst, U. 2010. Elastomere Friction: eory, Experi-
ment and Simulation. Springer.
https://doi.org/10.1007/978-3-642-10657-6
Choi, J. H.; Cho, J. R.; Woo, J. S.; Kim, K. W. 2012. Numerical
investigation of snow traction characteristics of 3-D patterned
tire, Journal of Terramechanics 49(2): 81–93.
https://doi.org/10.1016/j.jterra.2012.01.003
Deng,Z.; Qi, Z. T.; Dong,Z.; He,P.; Han,C.; Ren, S. 2013. A
road surface identication method for a four in-wheel-motor
drive electric vehicle, International Journal of Biomechatronics
and Biomedical Robotics 2(2/3/4): 87–92.
https://doi.org/10.1504/IJBBR.2013.058721
Dugo,H.; Fancher, P. S.; Segel, L. 1970. An analysis of tire trac-
tion properties and their inuence on vehicle dynamic per-
formance, SAE Technical Paper 700377.
https://doi.org/10.4271/700377
EC. 2009. Regulation (EC) No 1222/2009 of the European Parlia-
ment and of the Council of 25 November 2009 on the Labelling
of Tyres with Respect to Fuel Eciency and Other Essential
Parameters. Available from Internet:
http://data.europa.eu/eli/reg/2009/1222/oj
Ella,S.; Formagne, P.-Y.; Koutsos,V.; Blackford; J. R. 2013. In-
vestigation of rubber friction on snow for tyres, Tribology
International 59: 292–301.
https://doi.org/10.1016/j.triboint.2012.01.017
Enisz,K.; Szalay,I.; Kohlrusz,G.; Fodor, D. 2015. Tyre–road fric-
tion coecient estimation based on the discrete-time extend-
ed Kalman lter, Proceedings of the Institution of Mechanical
Engineers, Part D: Journal of Automobile Engineering 229(9):
1158–1168. https://doi.org/10.1177/0954407014556115
Farroni, F. 2016. T.R.I.C.K.– tire/road interaction characteriza-
tion & knowledge– a tool for the evaluation of tire and vehi-
cle performances in outdoor test sessions, Mechanical Systems
and Signal Processing 72–73: 808–831.
https://doi.org/10.1016/j.ymssp.2015.11.019
Hac,A.; Bodie, M. O. 2002. Improvements in vehicle handling
through integrated control of chassis systems, International
Journal of Vehicle Autonomous Systems 1(1): 83–110.
https://doi.org/10.1504/IJVAS.2002.001807
Han, I. 2017. Modelling the tyre forces for a simulation analysis
of a vehicle accident reconstruction, Proceedings of the Insti-
tution of Mechanical Engineers, Part D: Journal of Automobile
Engineering 231(1): 16–26.
https://doi.org/10.1177/0954407016630449
Heinrich,G.; Klüppel, M. 2008. Rubber friction, tread deforma-
tion and tire traction, Wea r 265(7–8): 1052–1060.
https://doi.org/10.1016/j.wear.2008.02.016
Higgins, D. D.; Marmo, B. A.; Jeree, C. E.; Koutsos,V.; Black-
ford, J. R. 2008. Morphology of ice wear from rubber–ice
friction tests and its dependence on temperature and sliding
velocity, We a r 265(5–6): 634–644.
https://doi.org/10.1016/j.wear.2007.12.015
424 J. Pokorski et al. Inuence of exploitation conditions on anti-skid properties of tyres
Klempau, F. 2001. Development of a friction prediction system,
in 2nd International Colloquium on Vehicle Tyre Road Interac-
tion, 23 February 2001, Florence, Italy, 1–17.
Li,Y.; Zhang,J.; Guan, X. 2012. Estimation of tyre–road friction
coecient, International Journal of Vehicle Systems Modelling
and Testing 7(3): 285–302.
https://doi.org/10.1504/IJVSMT.2012.048942
Makowski,M.; Knap, L. 2014. Reduction of wheel force varia-
tions with magnetorheological devices, Journal of Vibration
and Control 20(10): 1552–1564.
https://doi.org/10.1177/1077546312472916
Nam,K.; Fujimoto,H.; Hori, Y. 2015. Design of an adaptive slid-
ing mode controller for robust yaw stabilisation of in-wheel-
motor-driven electric vehicles, International Journal of Vehicle
Design 67(1): 98–113.
https://doi.org/10.1504/IJVD.2015.066474
Pacejka, H. 2012. Tire and Vehicle Dynamics. Butterworth-
Heinemann. 672 p.
Parczewski,K.; Wnęk, H. 2015. e tyre characteristics of the
physical model used to investigate the lateral stability of a
vehicle, Proceedings of the Institution of Mechanical Engineers,
Part D: Journal of Automobile Engineering 229(10): 1419–
1426. https://doi.org/10.1177/0954407014563734
Patel,N.; Edwards,C.; Spurgeon, S. K. 2008. Tyre–road friction
estimation: a comparative study, Proceedings of the Institution
of Mechanical Engineers, Part D: Journal of Automobile Engi-
neering 222(12): 2337–2351.
https://doi.org/10.1243/09544070JAUTO859
Persson, B. N. J. 1998. On the theory of rubber friction, Surface
Science 401(3): 445–454.
https://doi.org/10.1016/S0039-6028(98)00051-X
Pinnington, R. J. 2009. Rubber friction on rough and smooth
surfaces, We a r 267(9–10): 1653–1664.
https://doi.org/10.1016/j.wear.2009.06.011
Pokorski,J.; Reński,A.; Sar, H. 2012. Investigation of adhesion
characteristics of dierent tyre types in dierent weather con-
ditions, Journal of KONES: Powertrain and Transport 19(3):
363–369. https://doi.org/10.5604/12314005.1138147
Pokorski,J.; Reński,A.; Sar, H. 2015. System for investigation of
friction properties of the road surface, e Baltic Journal of
Road and Bridge Engineering 10(2): 126–131.
Radó, Z. 1994. A Study of Road Surface Texture and Its Relation-
ship to Friction. PhD esis, Pennsylvania State University, US.
Singh, K. B.; Taheri, S. 2015. Estimation of tire–road friction co-
ecient and its application in chassis control systems, Systems
Science & Control Engineering 3(1): 39–61.
https://doi.org/10.1080/21642583.2014.985804
Sjahdanulirwan, M. 1993. An analytical model for the prediction
of tyre-road friction under braking and cornering, Interna-
tional Journal of Vehicle Design 14(1): 78–99.
Skouvaklis,G.; Blackford, J. R.; Koutsos, V. 2012. Friction of rub-
ber on ice: A new machine, inuence of rubber properties
and sliding parameters, Tribology International 49: 44–52.
https://doi.org/10.1016/j.triboint.2011.12.015
Wambold, J. C.; Antle,C.; E.; Henry, J. J.; Radó, Z. 1995. Interna-
tional PIARC Experiment to Compare and Harmonize Texture
and Skid Resistance Measurement. Permanent International
Association of Road Congresses (PIARC). 423 p.
Will, A. B.; Zak, S. H. 2000. Antilock brake system modelling and
fuzzy control, International Journal of Vehicle Design 24(1):
1–18. https://doi.org/10.1504/IJVD.2000.001870
Woodward,D.; Friel, S. 2017. Predicting the wear of high friction
surfacing aggregate, Coatings 7(5): 71.
https://doi.org/10.3390/coatings7050071
Zhao,J.; Zhang,J.; Zhu, B. 2016. Coordinative traction control
of vehicles based on identication of the tyre–road friction
coecient, Proceedings of the Institution of Mechanical En-
gineers, Part D: Journal of Automobile Engineering 230(12):
1585–1604. https://doi.org/10.1177/0954407015618041
