SIST EN 13036-8:2025

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN 13036-8:2009
Značilnosti cestnih in letaliških površin - Preskusne metode - 8. del: Določanje
indeksov prečne neravnosti in prečnega nagiba
Road and airfield surface characteristics - Test methods - Part 8: Determination of
transverse unevenness and crossfall indices
Oberflächeneigenschaften von Straßen und Flugplätzen - Prüfverfahren - Teil 8:
Bestimmung von Querunebenheit und Querneigung
Caractéristiques de surface des routes et aérodromes - Méthodes d'essais - Partie 8 :
Détermination des indices d'uni transversal et de dévers
Ta slovenski standard je istoveten z: EN 13036-8:2025
ICS:
17.040.20 Lastnosti površin Properties of surfaces
93.080.10 Gradnja cest Road construction
93.120 Gradnja letališč Construction of airports
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 13036-8
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2025
EUROPÄISCHE NORM
ICS 93.080.10 Supersedes EN 13036-8:2008
English Version
Road and airfield surface characteristics - Test methods -
Part 8: Determination of transverse unevenness and
crossfall indices
Caractéristiques de surface des routes et aérodromes - Oberflächeneigenschaften von Straßen und
Méthodes d'essais - Partie 8 : Détermination des Flugplätzen - Prüfverfahren - Teil 8: Bestimmung von
indices d'uni transversal et de dévers Indizes für die Querunebenheit und die Querneigung
This European Standard was approved by CEN on 9 June 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 13036-8:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviated terms . 9
5 Pre-processing of the transverse profile . 10
5.1 General. 10
5.2 Transverse profile measured with a traffic speed profilometer . 11
6 Computation of indices . 14
6.1 General. 14
6.2 Rut depth indices . 15
6.2.1 General. 15
6.2.2 The Sliding Wire Rut Depth method (R ) . 16
SW
6.2.3 The Total Transverse Unevenness method (R ) . 16
TTU
6.2.4 The Left and Right Rut Depth method (R and R ) . 17
L R
6.3 Other transverse indices . 18
6.3.1 General. 18
6.3.2 Ridge Height (R ) . 19
H
6.3.3 Indices for water in ruts . 19
6.3.4 Miscellaneous transverse indices . 21
6.4 Crossfall index (CF ) . 22
R
7 Measurement devices and their application . 24
7.1 Measurement devices . 24
7.2 Lateral positioning . 25
8 Accuracy . 25
8.1 General. 25
8.2 Resolution of presented indices . 25
8.3 Precision . 25
8.4 Bias . 26
9 Safety . 26
10 Report for project level measurements . 27
Annex A (informative) Measurement of indices of transverse unevenness and irregularities with
a straightedge . 28
Annex B (informative) The use of transverse indices . 31
Annex C (informative) Implementation guide . 32
Annex D (informative) Evaluating and using the transverse indices . 33
Annex E (informative) Other transverse indices . 34
Bibliography . 40
European foreword
This document (EN 13036-8:2025) has been prepared by Technical Committee CEN/TC 227 “Road
materials”, the secretariat of which is held by BSI- British Standards Institution.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2026, and conflicting national standards shall
be withdrawn at the latest by January 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document will supersede EN 13036-8:2008.
— the title of the document has changed from Determination of transverse unevenness to Determination
of transverse unevenness and crossfall indices;
— routines for pre-processing the transverse profile before calculating the indices;
— the standard includes procedures to calculate transversal unevenness for profilometers with a
densely collected transverse profile;
— the standard contains more possibilities to characterize the transversal unevenness and crossfall.
The calculation routines for all indices have been updated and better described:
— two additional principles to describe the rut depth are added, sliding wire rut depth and total
transverse unevenness;
— one additional principle to describe crossfall is added, crossfall line;
— the definition of Edge slump is updated;
— distance between rut buttons is added;
— rut width is added;
— rut area is added;
— water area is added;
— step height has been removed;
— a link to an implementation guide to calculate the indices has been added.
EN 13036 consists of the following parts, under the general title Road and airfield surface characteristics
— Test methods:
— Part 1: Measurement of pavement surface macrotexture depth using a volumetric patch technique
— Part 2: Assessment of the skid resistance of a road pavement surface by the use of dynamic measuring
systems
— Part 3: Measurement of pavement surface horizontal drainability
— Part 4: Method for measurement of slip/skid resistance of a surface: the pendulum test
— Part 5: Determination of longitudinal unevenness indices
— Part 6: Measurement of transverse and longitudinal profiles in the evenness and megatexture
wavelength ranges
— Part 7: Irregularity measurement of pavement courses: the straightedge test
— Part 8: Determination of transverse unevenness and crossfall indices
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Part 2 is available as a CEN/TS.
Introduction
Road surface unevenness and crossfall affects safety, ride comfort, environmental impact, and the
technical performance of roads. When a road is in use the surface will be deformed and worn due to the
traffic load. Contributing causes of surface degradation are the time in use, the traffic load,
weather/climate conditions, geological conditions, used materials as well as the strength of the road
construction. To simplify quantifying the degree of deformation and wear, indicators have been
developed that are based on the transverse (perpendicular to the direction of traffic flow) and
longitudinal (parallel to the direction of traffic flow) profiles. Rut depth is such an indicator of the
technical performance of the surface course that arises from permanent deformation from traffic loads
and wear from the tyre and pavement interaction. A road with a moderate level of rut depth in
combination with a sufficient crossfall will lower or even eliminate the risk of aquaplaning in wet
conditions and as far as rut depth is concerned, a low or moderate level will ensure sufficient lateral
stability of vehicles with trailers (especially by a lane change). More than two wheel paths can occur due
to wear from heavy traffic and cars since the transverse location of the wheels differs. This is most
prominent in countries where studded tyres are used. The transverse unevenness encompasses aspects,
such as: irregularities in the transverse profile including the longitudinal ruts and deformations in the
wheel paths caused by the traffic. Measurement devices measuring the transverse profiles can be divided
into two groups:
— slow or stationary equipment, such as the straightedge for irregularities and longitudinal ruts;
— equipment used at traffic speed, such as profilometers, which depending on the characteristics of the
device, are suitable for measuring single sections as well as longer road sections and networks.
The quantified unevenness indices derived from this document are useful support for quality control of
newly laid pavement surfaces, especially with respect to the evidence of irregularities due to improper
laying and/or compacting actions. It is also useful for evaluating the condition of pavements in service as
part of routine condition monitoring programs, and finally as indices to be used for maintenance planning
of resurfacing activities on pavements in use. The derived indices are portable in the sense that they can
be obtained from transverse profiles measured with any suitable instrument.
All indices described in this document are related to the actual lane and direction of the road at which the
measurement is done.
1 Scope
This document specifies the mathematical processing of digitized transverse profile measurements to
produce indices in the transverse direction for unevenness, other defects and crossfall. The document
describes the calculation methods of the indices, such as irregularities, (1) rut depth, (2) ridge height, (3)
water depth and area, (4) crossfall, and how to evaluate and report the indices. It also describes
possibilities to do further analysis to examine defects and problems on the road that can be seen in the
transverse profile. The latter is described in Annex E.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 13036-6, Road and airfield surface characteristics - Test methods - Part 6: Measurement of transverse
and longitudinal profiles in the evenness and megatexture wavelength ranges
EN 13036-7, Road and airfield surface characteristics - Test methods - Part 7: Irregularity measurement of
pavement courses : the straightedge test
ISO 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in
probability
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
acquisition repetition interval
absolute value of the difference of abscissa between two longitudinal adjacent points of the digitised
transverse profiles
Note 1 to entry: Low level, typical 0,1 m to 1 m, see Figure 1 for further information.
3.2
bias
difference between the expectation of the test result and an accepted reference value
Note 1 to entry: Bias is the total systematic error as contrasted to random error. There can be one or more
systematic error components to the bias. A large systematic difference from the accepted reference value is reflected
by a large bias value (see ISO 3534-1).
3.3
crossfall
transverse slope across a lane
Note 1 to entry: Crossfall is measured perpendicular to the centre line and expressed as a percentage (the ratio of
the height difference of the transverse profile and the profile length) with a positive value when the right end of the
transverse profile is lower than its left end (for right-hand traffic and the opposite for left-hand traffic).
Note 2 to entry: An alternative procedure to calculate crossfall is described in the informative Annex E.
3.4
distance between rut bottoms
distance between the rut bottom in the right and left side of the lane, expressed in mm
3.5
edge slump
degree of deformation of the part of the measured lane closest to the road shoulder, expressed in mm
3.6
inner part of the transverse profile
part of the transverse profile, closest to the road centre (the right side of the transverse profile for left-
hand traffic and the opposite for right-hand traffic)
3.7
outer part of the transverse profile
part of the transverse profile closest to the road shoulder (the left side of the transverse profile for left-
hand traffic and the opposite for right-hand traffic)
3.8
pavement
structure, composed of one or more courses, to assist the passage of traffic over terrain
3.9
surface course
wearing course
upper layer of the pavement, which is in contact with the traffic
[SOURCE: EN 13036-7:2003].
3.10
precision
closeness of agreement between independent test results obtained under stipulated conditions
Note 1 to entry: Precision depends only on the distribution of random errors. The measure of precision is usually
computed as a standard deviation of the test results. Less precision is reflected by a larger standard deviation (see
ISO 3534-1).
3.11
profilometer
measurement device that operates at normal traffic speed, used to measure different properties of the
road surface, e.g., longitudinal and transverse profiles, texture and road geometry
3.12
repeatability
variation in measurements made by the same machine, under the same condition, operated by the same
crew on the same section of road in a short period of time
3.13
reporting repetition interval
measurements made over the road surface which are often analysed using shorter parts or samples to
allow for a more precise description of the measured transverse profile and which is the length of such a
sample
Note 1 to entry: See Figure 1 for further information.
3.14
ridge height
transversal unevenness index, especially designed for minor roads where ruts more seldomly appear,
expressed in mm
3.15
rut area
area for left and right part of the transverse profile, calculated as the sum of areas for the left and right
side of the profile, expressed in mm
3.16
rut depth
transverse unevenness calculated as the maximum deviation between the transverse profile of a
pavement surface and a virtual straight reference line, expressed in mm
3.17
rut width
width of the left and right rut, calculated from the left and right side of the transverse profile, expressed
in mm
3.18
sampling interval
travelled distance between two consecutive measured transverse profiles (raw data for calculating
acquisition repetition interval)
Note 1 to entry: See Figure 1 for further information
3.19
section
length of road between defined points (e.g., location references, specific features, or measured distances)
comprising a number of subsections over which a continuous sequence of measurements is made
3.20
straightedge
mechanical device used to measure individual irregularities of the road surface statically
3.21
surface wire method
method to calculate rut depth where a wire is stretched between two endpoints and rests on any high
points in between, used to define rut depth as the maximum perpendicular distance between the wire
and the transverse profile
3.22
theoretical sum of water area
indicator of the sum of area(s) created between a horizontal reference line and the measured profile,
calculated separately for the left and right part of the transverse profile, expressed in mm
2 2
Note 1 to entry: Typical water area level is between 0 and 10 000 mm , corresponding to 0 to 1 dm .
3.23
theoretical water depth
indicator of the maximum distance between a horizontal reference line and the measured profile,
calculated separately for the left and right part of the transverse profile, expressed in mm
Note 1 to entry: Theoretical water depth and area are indicators of the risk for aquaplaning. The theoretical water
depth in a depression or dip is also called “ponding depth”.
3.24
transverse acquisition sampling interval
transversal distance between two consecutive measured data points, at the surface, in a discrete
transverse profile
Note 1 to entry: If the transverse acquisition sampling interval is not equal along the profile, the mean value is
calculated.
3.25
transverse profile
geometrical shape of the road surface in the transverse direction, described by the height of the
measurement points, expressed in mm
3.26
trueness
closeness of agreement between the average value obtained from large series of test results and an
accepted reference value
Note 1 to entry: The measure of trueness is usually expressed in terms of bias and reflects the total systematic error
as contrasted to random error. There may be one or more systematic error components to the trueness. A large
systematic difference from the accepted reference value is reflected by a large value (see ISO 3534-1).
3.27
wheel path
contact area of the pavement surface and wheel, corresponding to where most vehicle wheel passages
are concentrated
4 Symbols and abbreviated terms
For the purposes of this document, the following symbols and abbreviated terms apply.
CF crossfall line
L
CF crossfall regression
R
DRB distance between rut bottoms
ES edge slump
R greatest rut depth of R and R
L R
RA rut area of left wheel path
L
RA rut area of right wheel path
R
R ridge height
H
R rut depth in left wheel path
L
R rut depth in right wheel path
R
R sliding wire rut depth at any transverse position of the profile
SW
R total transverse unevenness for whole transverse profile
TTU
RW rut width of left wheel path
L
RW rut width of right wheel path
R
WA water area at left side of the lane
L
WA water area at right side of the lane
R
WD water depth in left wheel path
L
WD water depth in right wheel path
R
5 Pre-processing of the transverse profile
5.1 General
The requirement of needed accuracy, resolution, physical width and spacing of the measurement points
that characterize the transverse profile is selected according to EN 13036-6. A description of the different
definitions is shown in Figure 1. The document handles classes of:
— vertical resolution of transverse profiling (sensor resolution);
— transverse acquisition sampling interval of transverse profiling (number of measurement points);
— sampling interval of transverse profiling (longitudinally) (raw data for calculating acquisition
repetition interval);
— acquisition repetition interval of transverse profiling (longitudinally) (lowest level of transverse
profile for calculation of indices, typical 0,1 m to 1 m);
— reporting repetition interval of transverse profiling (longitudinally) (the reporting interval of
indices, section mean values, typical 10 m to 100 m);
Dimensions in metres
Key
a sampling interval (sensor dependent length);
b acquisition repetition interval. Indices are calculated;
c reporting repetition interval. Indices are averaged and presented.
Figure 1 — Description of the terms sampling interval, acquisition repetition interval and
reporting repetition interval
5.2 Transverse profile measured with a traffic speed profilometer
The most common way to measure and characterize the transverse profile is with a traffic speed
profilometer. When characterizing the transverse profile, for the purpose of calculating transverse
unevenness, the effect from the texture should be minimized. Today there are two possible techniques
used for traffic speed profilometers: (1) point laser sensors and (2) scanning laser sensors.
A typical point laser sensor is working with a high frequency (normally 16 – 64 kHz) and the “raw”
readings from the sensor shall be averaged at the acquisition repetition interval in order to filter out the
influence of the noise in the sensor and the pavement texture. At least 50 readings per 0,1 m in the
longitudinal direction shall be used for this purpose. An average of the readings is used from each sensor
to characterize the shape of the transverse profile at the acquisition repetition interval.
The scanning laser technique has a high resolution of measurement points in the transverse direction, in
contrast to the point lasers.
NOTE Many modern sensors with scanning technique also have a high resolution in the longitudinal direction.
The raw transverse profile sometimes has a transverse sampling interval smaller than 1 mm that is
influenced by the pavement texture as well as the noise in the sensor. The transverse profile at the
acquisition repetition interval is calculated from one or more transverse profiles at the sampling interval
as the average in the longitudinal direction for the corresponding lateral position. To describe the
transverse profile when calculating the transverse indices, one shall first filter the data. The filtering of
the transverse profile (at acquisition repetition interval) has two purposes: to get rid of noise in the
sensor and to eliminate the effect of the pavement texture. The raw transverse profile should be filtered
with a 100 mm three-pole low pass Butterworth filter (forward reverse). To eliminate edge effects of the
filter, the raw profile should be mirrored before filtering, see Figure 2. The mirroring is done around both
the horizontal and the lateral axis. The minimum length of the mirrored part of the profile shall be
300 mm for enough lead in and out time for the Butterworth filter. The mirroring procedure is described
below.
The transverse profile is described by n data points.
The mirroring at the left and right side of the profile is done by using the left and right half of the profile
with the following Formulae (1) and (2).
Example, if a transverse profile is 4 m wide and has 4001 datapoints, 1 sample every 1 mm, the mirroring
procedure will use point 0 to 2 000 for the left side and 2 000 to 4 000 for the right side.
nn−
last 0
n goes from 0 to (1)
h hh−
−×1 n 0 n
( )
lp lp− lp
0 n
−×1 n
( )
where
th
n is the index for the n datapoint in the transverse profile from the left side (seen in the
driving direction);
n is the index for the first datapoint (leftmost) in the transverse profile;
n is the index for the last datapoint (rightmost) in the transverse profile;
last
th
lp is the lateral position for the n datapoint;
n
th
h is the profile height for the n datapoint.
n
=
=
nn−
last 0
Mirrored points at left side n=−×1 to− 1
n
last
n goes from 1 to
h hh−
n
n +n nn−
( ) ( )
last
last last
 
lp =lp+ lp− lp (2)
 
nn
n +−n nn
( ) ( )
last last
last last
 
where
th
n is the index for the n datapoint in the transverse profile from the left side (seen in the
driving direction);
n is the index for the first datapoint (leftmost) in the transverse profile;
n is the index for the last datapoint (rightmost) in the transverse profile;
last
th
lp is the lateral position for the n datapoint;
n
th
h is the profile height for the n datapoint.
n
n
last
Mirrored points at right side nn=++1 to n
last last
The entire (or any other part of the) transverse profile at acquisition repetition interval can be used to
characterize transverse indices, provided that the mirroring has been done.
=
Dimensions in millimetres
Key
a original profile
b mirrored expansion
Figure 2 — The expanded and mirrored transverse profile, prepared for filtering. The orange
profile is the original profile. The blue expansion is the mirroring
The transverse profile shall be presented with the crossfall included, this applies also for the calculations
described in Clause 6 and Annex E.
6 Computation of indices
6.1 General
A guide for implementation of the indices described in this document is available in the informative
Annex C.
Examples of how to evaluate and use the transverse indices can be found in the informative Annex D.
Furthermore, possible use, reporting repetition interval and measurement methods for the different
transversal unevenness indices in various situations can be found in the informative Annex B.
The described indices in this document are in some cases calculated for the left and right side of the
measured lane. This implies for left-hand traffic that the left side of the profile is close to the road shoulder
and the right side is close to the centre of the road. For right-hand traffic it is the opposite. The transverse
profile describes the shape of the measured lane from left to right transversally in the driving direction.
6.2 Rut depth indices
6.2.1 General
The unevenness of the transverse profile can be characterized by the following indices:
R , R , R , R and R
H L R TTU SW
In Figure 3, the indices are illustrated related to their position in a transverse profile.

Key
RH ridge height
RL rut depth left
RR rut depth right
R total transverse unevenness
TTU
R sliding wire rut depth
SW
NOTE In this example RSW and RR are found at the same position.
Figure 3 — Overview of different rut depth indices
Ruts in the wearing course manifest as a continuous depression in the longitudinal direction in the wheel
paths. The texture of the surface is not a part of the rut depth and should be eliminated by filtering, in an
appropriate way (as described in 5.2).
6.2.2 The Sliding Wire Rut Depth method (R )
SW
The calculation of the lowest level of rut depth is done according to the surface wire method applied on
the transverse profile at the acquisition repetition interval. The rut depth is defined as the maximum
deviation between a two meter virtual reference wire when both ends of the wire is attached at the profile
and when the wire rests on any high points in between. If the measurement points in the transverse
profile do not enable using exactly a two meter wire, the profile should first be linear interpolated to a
distance that allows this. The interpolated profile should be used in the calculation described above. The
deviation shall be measured perpendicular from the wire to the transverse profile. The wire slides or
moves one step at a time (using all possible measurement points or interpolated measurement points),
from one side to the other of the entire width of the transverse profile and the rut depth is calculated for
each position. The maximum rut depth of all possible lateral positions represents the result (rut depth)
at the acquisition repetition interval, see Figure 4. The result at the reporting repetition interval is an
arithmetic average of the rut depths from the acquisition repetition intervals. An index is used to indicate
the wire length (an example is shown in Figure 4).
Dimensions in millimetres
Key
s1 sliding wire rut depth for position s1
s2 sliding wire rut depth for position s2
up to sx sliding wire rut depth for position sx (x=last possible position to search for rut)
Figure 4 — Sliding wire rut depth calculated at a 3,2 m wide transversal profile, R = s6
SW2,0
6.2.3 The Total Transverse Unevenness method (R )
TTU
The calculation of the total transverse unevenness is done according to the surface wire method on the
transverse profile at the acquisition repetition interval. The unevenness is calculated as the maximum
perpendicular distance between the transverse profile and a virtual reference wire when both ends of
the wire are attached at the start and end of the profile and when the wire rests on any high points in
between (see Figure 5a and Figure 5b). The maximum perpendicular distance between the wire and the
profile represents the result (rut depth) at the acquisition repetition interval. The result for the reporting
repetition interval is an arithmetic average of the rut depths at acquisition repetition interval. An index
is used to indicate the length of the wire used in the calculation, e.g. RTTU3,2 = 11,3 mm for a 3,2 m wide
transverse profile. In case the measurement system automatically detects the transversal profile width
based on the road markings an index a (auto detect, R ) should be used instead of the actual wire width.
TTUa
NOTE 1 The height of the road markings could significantly influence the rut depth results.
Dimensions in millimetres
a) Transverse profile with a low midpoint

b) Transverse profile with a high midpoint
Key
s1 rut depth for position s1
s2 rut depth for position s2
up to s15 rut depth for position s15
NOTE 2 The wire is stretched between the outer measurement points.
NOTE 3 The wire is stretched between the outer measurement points and resting at the middle
highest measurement point.
Figure 5 — Total transversal unevenness calculated at a 3,2 m wide transversal profile,
R = s13
TTU3,2
6.2.4 The Left and Right Rut Depth method (R and R )
L R
The calculation of rut depth is done according to the surface wire method on the transverse profile at the
acquisition repetition interval. The length of the wires shall be defined as 60 % of the total width of the
transverse profile. It will give an overlap of 20 % of the total width in the middle. E.g. a 3,2 m wide
transverse profile will give a wire length of 1,92 m for the left and right side. If the measurement points
of the transverse profile do not enable using a wire of exactly 60 % of the measurement width, the profile
should first be linear interpolated to a distance that allows this. The interpolated profile should be used
in the calculation. The rut depth is defined as the maximum distance between a virtual reference wire
when both ends of the wire are attached at the profile and when the wire rests on any high points in
between (see Figure 6a and Figure 6b). The deviation shall be measured as the greatest perpendicular
distance from the straight wire to the transverse profile. The maximum perpendicular distance between
the wire and the profile represents the result (rut depth) at the acquisition repetition interval. The result
for the reporting repetition interval is an arithmetic average of the rut depths at acquisition repetition
interval. An index is used to indicate the length of the wire used in the calculation, e.g. R = 10,2 mm for
L1,9
a 3,2 m wide transverse profile where wire length 1,92 m is used in the calculation. In case the
measurement system automatically detects the transversal profile width based on the road markings an
index a (auto detect, R ) should be used instead of the actual wire width.
La
a) Rut depth — Left
b) Rut depth — Right
Key
a 60 % of measurement width (left side)
b 60 % of measurement width (right side)
s1 rut depth for position s1
s2 rut depth for position s2
up to sx rut depth for position sx (x=last possible position to search for rut)
Figure 6 — Rut depth calculated at a 3,2 m wide transversal profile, R = s5
R1,9
6.3 Other transverse indices
6.3.1 General
The transverse profile can be used to describe other important properties for the purpose of selecting
maintenance objects and to describe the condition of the road. Some properties can also be used for
control of new constructed roads. In the following subclauses are the definitions described for calculating
ridge height (see 6.3.2), water depth (see 6.3.3.2), water area (see 6.3.3.3) and crossfall (see 6.4).
NOTE 1 Ridge height is an alternative indicator of the evenness of the transverse profile. Other defects appear at
the secondary roads such as edge deformation from heavy traffic which not necessary can be detected by the rut
depth indices. Ridge height can be used in combination with rut depth to better characterize the transverse
unevenness for this category of roads.
NOTE 2 Other indices used to describe the characteristics of the transverse profile can be found in the
informative Annex E.
6.3.2 Ridge Height (R )
H
The calculation of ridge height is done by attaching a wire between the two points at the position of where
rut depth left and right have been located, according to 6.2.4. If rut depth left or right is zero, the wire is
attached 0,75 m from the centre of the profile, in the direction(s) to where rut depth is equal to zero. R
H
is defined as the maximum perpendicular distance between the wire and a measurement point at the
transverse profile. The selected point at the transverse profile could be above or below the wire. If the
maximum distance goes to a measurement point above the wire R is defined as positive and negative in
H
the opposite case. If the maximum perpendicular distance is found outside the interval 0,25 m and 1,20 m
from the centre of the profile, for either left or right rut depth, or both, a point, that is 1,20 m from the
centre of the transverse profile, is used to attach the wire.
In the specific case when the left or right rut depth is found outside the valid zone between 0,25 m and
1,2 m, 1,2 m is selected because the most probable shape of the profile is a heavily deformed section with
very wide deformation zones, rather than narrow ruts or deformations. If rut depth left or right is equal
to zero (less than 0,05 mm) the wire is attached 0,75 m from centre of the profile. This distance is selected
to match half the normal width between the wheels of a passenger car.
If the measurement points of the measured transversal profile do not enable using an attachment point
at exactly 0,75 m or 1,20 m from the centre of the profile, the profile should first be linear interpolated to
a distance that allows this. The interpolated profile should be used in the calculation described above.
The calculation is done from the transverse profile at the acquisition repetition interval. The result for
the reporting repetition interval is an arithmetic average of the ridge height at acquisition repetition
interval. An example is shown in Figure 7 below.
Dimensions in millimetres
Key
s1 ridge height for position s1
s2 ridge height for position s2
up to s11 ridge height for position s11
Figure 7 — Ridge height calculated at a 3,2 m wide transversal profile, R = s6
H
6.3.3 Indices for water in ruts
6.3.3.1 General
The theoretical amount of water that can fill the ruts of the road can be described in two alternative ways,
theoretical water depth and theoretical sum of water area. The measures are presented separately for
left and right side of the transverse profile. The left side is defined as 60 % of the total width of the
transverse profile. Correspondingly, the right side is defined. This gives an overlap of 20 % in the middle
of the profile.
6.3.3.2 Theoretical water depth left and right (WD and WD )
L R
A wire parallel to the horizon is lowered until two contact points between the wire and the transverse
profile is found where all measurement points between the contact points is under the line . If only one
contact point is found with the criteria above, no water can accumulate on the pavement surface and the
water depth equals to zero, WD = 0. If two contact points exist, the water depth is defined as the vertical
distance between the contact points of the wire and the lowest point in the transverse profile (between
the contact points). The search for contact points continues until the lowest point of the transverse profile
is reached. Multiple water depths can be found at left or right side. The maximum water depth of all found
water depths within one side of the transverse profile will represent the theoretical water depth. The
calculation is done from the transverse profile at the acquisition repetition interval. The result for the
reporting repetition interval is an arithmetic average of the water depth at acquisition repetition interval.
An example is shown in Figure 8 below.
Dimensions in millimetres
Key
a right side
b left side
WD water depth left
L
WDR water depth right
Figure 8 — Example of theoretical water depth at the left and right side of the transverse profile

A contact point can be between two measurement points. In that case the contact point is decided by the
intersection between a linear interpolated line between the two closest measurement point at each side of the
intersection and the wire defining water area.
6.3.3.3 Theoretical sum of water area left and right (WA and WA )
L R
The same procedures as in 6.3.3.2 are used to locate the theoretical water ponds in the transverse profile
when calculating the water area. The sum of the area(s) between the wire and the transversal profile is
calculated, instead of searc
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