Rural Flexible Roads Manual: Volume 1 of 3

Volume 1 of 3
Rural Flexible Roads Manual

Pavement Surface Condition Index
Department of Transport,
Tourism and Sport
October 2013
DOCUMENT CONTROL SHEET
Client Department of Transport, Tourism and Sport
Author PMS Pavement Management Services Ltd.
Document Title Rural Flexible Roads Manual
Document No. Issue 1, Rev. 1, November 2013
This Document DCS TOC Text Tables Figures Appendices

Comprises
1 1 47 2 0 0
Rev. Status Author(s) Reviewed By Office of Origin Issue Date
Rev. 0 Final Issue B. Mulry K. Feighan Galway 20 Apr 12
Rev. 1 Final Issue B. Mulry K. Feighan Galway 04 Nov 13
Issue 1, Rev. 1, Nov. 2013 1

Acknowledgements
This Manual was written by Dr. Kieran Feighan and Mr. Brian Mulry of PMS Pavement Management
Services Ltd. in collaboration with a Steering Group of the Department of Transport, Tourism and Sport.
The members of the Steering Group were as follows:
Name Organisation
Dominic Mullaney Department of Transport, Tourism and Sport
John McCarthy Department of Transport, Tourism and Sport
Paul Fox Local Government Management Agency
Peter Britton South Tipperary County Council
Liam Fitzgerald Carlow County Council
John McLaughlin Donegal County Council
Kieran Feighan PMS Pavement Management Services Ltd.
Brian Mulry PMS Pavement Management Services Ltd.
David O’Brien PMS Pavement Management Services Ltd.
Ken Dowling Compass Informatics Ltd.
Andy Day Compass Informatics Ltd.
The authors would like to acknowledge the very significant contribution from the Steering Group both in
terms of input to the manual content and in participation in a number of field trials to assess the
application of the manual and related software at local authority level. Additional participation and
contribution from other members of the above organisations was also made throughout the testing and
trialling process of the manual and technologies.
Issue 1, Rev. 1, Nov. 2013 2

Table of Contents
Acknowledgements ...............................................................................................................2
Table of Contents...................................................................................................................3
Section 1: Introduction...........................................................................................................4
Section 2: Pavement Distress – Flexible Pavements ................................................................5
Surface Defects.............................................................................................................................. 6
Ravelling ............................................................................................................................................................... 6
Bleeding................................................................................................................................................................ 8
Pavement Deformation ............................................................................................................... 10

Rutting ................................................................................................................................................................ 10
Surface Distortion............................................................................................................................................... 11
Cracks ......................................................................................................................................... 13
Alligator Cracking ............................................................................................................................................... 13
Edge Breakup/Cracking ...................................................................................................................................... 15
Other Cracking.................................................................................................................................................... 18
Surface Openings......................................................................................................................... 20
Patching.............................................................................................................................................................. 20
Potholes.............................................................................................................................................................. 22
Road Disintegration............................................................................................................................................ 23
Section 3: Rating Pavement Condition.................................................................................. 24

Table 1: The PSCI Rating System................................................................................................... 25
Rating 10 ..................................................................................................................................... 26
Rating 9 ...................................................................................................................................... 27
Rating 8....................................................................................................................................... 29
Rating 7....................................................................................................................................... 30
Rating 6....................................................................................................................................... 33
Rating 5....................................................................................................................................... 35
Rating 4....................................................................................................................................... 37
Rating 3....................................................................................................................................... 39
Rating 2....................................................................................................................................... 41
Rating 1....................................................................................................................................... 42
Section 4: Practical Advice on Rating Roads.......................................................................... 44

Inventory and Field Inspection ..................................................................................................... 44
Averaging and Comparing Sections .............................................................................................. 44
Section 5: Conclusions and Next Steps .................................................................................. 45

Table 2: Treatment Measures ...................................................................................................... 46
Section 6: Bibliography ........................................................................................................47
Issue 1, Rev. 1, Nov. 2013 3

Section 1: Introduction
A major function of a local authority is to use public funds to provide a comfortable, safe and
economical road surface. This requires balancing priorities and making difficult decisions in order to
manage pavements. Many local pavement networks are often managed informally, based solely on
the staff’s judgment and experience. While this process is both important and functional, using a
slightly more formalised technique can make it easier to manage pavements effectively.
Experience has shown that there are three especially useful steps in managing local roads:
1. Inventory all local roads.
2. Periodically evaluate the condition of all pavements.
3. Use the condition evaluations to set priorities for projects and select appropriate
treatments.
A comprehensive pavement management system involves collecting data and assessing several road
characteristics: roughness (ride), surface distress (condition), surface skid resistance and structure
(pavement strength and deflection). Managers can combine this condition data with economic analysis
to develop short-range and long-range plans for a variety of budget levels. However, many local
agencies lack the resources for such a full-scale system.
Since surface condition is the most vital element in any pavement management system, local agencies
can use the simplified Pavement Surface Condition Index (PSCI) rating system presented in this Rural
Flexible Roads Manual to evaluate their roads. The Flexible Roads ratings combined with other
inventory data (width, length, shoulder, pavement type, etc.) can be very helpful in planning future
budgets and priorities.
The PSCI condition rating system in this manual has been designed with a number of objectives in
mind. It should be simple to understand and implement by a wide range of survey personnel. No prior
experience in pavement rating should be necessary to carry out the rating procedure. The PSCI rating
system in Table 1 and Section 3 of this manual should be based only on visual pavement distresses.
The impact of surface-related distresses, structural-related distresses and other defects on the overall
rating system should be identified. The results of the rating system should be relatable to the
maintenance treatment categories specified for use on Non-National roads by the Department of
Transport, Tourism and Sport (DTTAS). Table 2 in Section 5: Conclusions and Next Steps of this manual
summarises the overall relationships between these factors.
This Manual is designed to improve the data collection and quality of visual surveying of non-national
roads within the local authorities of the Republic of Ireland. Substantial use was made of the template
provided by the Pavement Surface Evaluation and Rating (PASER) manuals produced by the
Transportation Information Center at the University of Wisconsin-Madison.
Issue 1, Rev. 1, Nov. 2013 4

Section 2: Pavement Distress – Flexible Pavements
This manual uses visual inspection to evaluate pavement surface conditions. The key to a useful
evaluation is identifying different types of pavement distress and linking them to a cause.
Understanding the cause for current conditions is extremely important in selecting an appropriate
maintenance or rehabilitation technique.
Deterioration has three general modes. These are

 Environmental deterioration due to weathering and aging
 Structural deterioration caused by repeated traffic loading
 Deterioration due to unsuitable materials (e.g. consolidation of subgrade, subsidence).
Pavement deterioration will result from contributions by one or more of the modes. It is important to
try to determine the relative contributions in order to select the most effective rehabilitation
techniques. The rate at which pavement deteriorates depends on its environment, traffic loading
conditions, original construction quality and interim maintenance procedures. Poor quality materials
or poor construction procedures can significantly reduce the life of a pavement. As a result, two
pavements constructed at the same time may have significantly different lives, or certain portions of a
pavement may deteriorate more rapidly than others. On the other hand, timely and effective
maintenance can extend a pavement’s life. Crack sealing and surface dressing can reduce the effect of
moisture on weakening of flexible road pavements.
With all of these variables it is easy to see why pavements deteriorate at various rates and why we find
them in various stages of disrepair. Recognising defects and understanding their causes helps us rate
pavement condition and select cost-effective repairs. The pavement defects shown on the following
pages provide a background for this process. Some defects are localised while others indicate that
problems may develop throughout the pavement. It is important to distinguish between local and
widespread defects. Assessing the conditions of actual roadways also involves looking for combinations
of these individual defects.
There are four major categories of common road surface defects on rural flexible roads:
Surface Defects
Ravelling
Bleeding
Pavement Deformation
Rutting
Surface Distortion
Cracks
Alligator Cracking
Edge Cracking and Breakup
Other Cracking (longitudinal, transverse, reflection, slippage, etc.)
Surface Openings
Patching
Potholes
Road Disintegration
Periodic inspection is necessary to provide current and useful evaluation data. It is recommended that
Flexible Road ratings be updated every two years, and an annual update is even better.
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SURFACE DEFECTS
Ravelling
Ravelling is progressive loss of binder and aggregate chippings from the pavement surface. Ravelling
can be caused by stripping of the bituminous film from the aggregate, binder hardening due to aging,
poor compaction especially in cold weather construction, insufficient binder content or poor quality
aggregate. In addition, ravelling can be caused by the action of tracked vehicles or oil spillage.
Moderate Ravelling. Small aggregate particles have worn away exposing tops of large aggregate.
Severe Ravelling. Most of the new surface has been lost, exposing the older surface beneath.
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SURFACE DEFECTS
Ravelling
Moderate Ravelling evident in wheelpaths.
Loss of surface material at the edge of the road. This is ravelling, not edge breakup.
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SURFACE DEFECTS
Bleeding
Bleeding or fatting up is a film of excess bituminous material on the pavement surface which creates a
shiny reflective surface that usually becomes sticky in hot weather. In surface dressings, it is usually
caused by excessive embedment of the chippings or too high a rate of spread of the binder. Repair by
the application of a properly designed surface treatment to restore adequate skid resistance or thin
overlay if additional strength is required.
Bleeding/Fatting-up of binder needs repair.
Bleeding. Dark, shiny areas extending along the wheelpaths.

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SURFACE DEFECTS
Bleeding
Bleeding. Dark, shiny areas show where binder has worked to surface.
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PAVEMENT DEFORMATION
Rutting
Rutting is a permanent longitudinal deformation in the wheel paths caused by traffic loading. It
occurs due to the displacement of material, creating channels in the wheel paths. Some uplift may
also occur along the sides of the rut. It is caused by traffic compaction or sideways movement of
unstable material. Severe rutting (over 50mm) may be caused by base or subgrade consolidation. It
is a form of structural failure caused by repeated traffic loading.
Severe Rutting over 50mm in depth evident in wheel path.
Severe Rutting caused by poor base or subgrade problems.
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Surface Distortion
All permanent surface deformation, with the exception of rutting, is identified as surface distortion.
Rutting is a permanent longitudinal deformation in the wheel paths caused by traffic loading.
Surface distortion can be caused by poor construction, improper mix design or settlement of the
subgrade. Distortion includes depressions or sags which are defined as small abrupt downward
displacements producing flat irregular shaped basins. Other pavement distortions maybe caused by
shoving, settling, frost heave etc. with longer wavelengths. Surface distortions are not caused by
traffic loading. This distress can have a significant effect on driver and passenger comfort. Moderate
surface distortion will reduce the driver comfort speed to less than 50 km/hr. Severe surface
distortion will reduce the driver comfort speed to less than 30 km/hr.
Significant depression visible in concentrated area.
Depression in subsided area.
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Surface Distortion
Surface Distortion (note road marking on left edge).
Surface deformation and shape problems (note road marking on left edge for reference).
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CRACKS
Alligator Cracking
Alligator cracking is a series of interconnected cracks forming small, many-sided, sharp-angled
polygons ranging in size from about 25mm to 125mm resembling chicken wire or the skin of an
alligator. It’s caused by fatigue failure of the surface due to traffic loading and very often also due to
inadequate base or subgrade support.
Alligator cracking may comprise;
 Fine, longitudinal hairline cracks running parallel to each other and with none or only a
few interconnecting cracks. There is no spalling which is a breakdown of material along
the sides of a crack.
 A pattern of parallel and interconnecting cracks that may be lightly spalled.
 A well-defined pattern of interconnected polygon shaped cracks which are spalled at the
edges. Some pieces may appear to be loose or may appear to rock under traffic.
Repair by excavating localised areas and replacing base and surface. Large areas require overlay or
reconstruction. Improvements in drainage may often be required.
Characteristic “Chicken wire” crack pattern shows smaller pavement pieces and patching.
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CRACKS
Alligator Cracking
Open alligator cracking with settlement along lane edge most likely due to very weak subgrade.
Wide area of alligator cracking.
Issue 1, Rev. 1, Nov. 2013 14

CRACKS
Edge Breakup/Cracking
Edge breakup can be caused by inadequate pavement width, inadequate lateral support to the
pavement, moisture penetration, poor drainage or frost action. It is accelerated by repeated traffic
loading. Edge breakup is identified as
- Any singular or multiple cracking within 300 mm of the pavement edge.
- Pavement edge showing considerable breakup with some portions of the edge having been removed.
- Breakup of the pavement edge including a mix of potholing, cracking and patching along the
pavement edge.
Edge breakup differs from loss of surface (Ravelling) at the pavement edge as it is a structural
distress caused by traffic loading. Edge breakup can be distinguished from Ravelling by the presence
of cracking and loss of some or all the underlying pavement layers at the pavement edge.
Multiple longitudinal cracks in the pavement edge indicate a need for strengthening with an overlay
or reconstruction.
Edge Breakup identified by cracking at the edge of the road pavement.
Issue 1, Rev. 1, Nov. 2013 15

CRACKS
Edge Breakup at the edge of the road pavement.
Edge breakup/cracking and material loss from weakened subbase and traffic loads.
Issue 1, Rev. 1, Nov. 2013 16

CRACKS
Multiple cracking within 300 mm of the pavement edge.
Potholes and loss of pavement material along the pavement edge.
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CRACKS
Other Cracking
Longitudinal cracks are parallel to the pavement centreline. Transverse cracks extend across the
pavement at approximately right angles to the pavement centreline and are often regularly spaced.
Transverse cracking at regular, short intervals will often be seen on boggy ground.
These types of cracking can be caused by reflection cracking from cracking or joints in the
underlying pavement layers or by movement of the underlying layers due to moisture penetration,
temperature changes, binder hardening due to aging or traffic loading. The crack edges can further
deteriorate by ravelling, eventually eroding the adjacent pavement.
Other cracking also includes Slippage cracking which are crescent or rounded cracks. They are
caused by slippage between an overlay and the underlying pavement due to a low-strength surface
mix or poor bond. Slippage is most likely to occur at areas where traffic is stopping and starting,
turning or braking.
Regular pattern of transverse cracking – bleeding also evident in the wheelpaths.
Issue 1, Rev. 1, Nov. 2013 18

CRACKS
Other Cracking
Slippage cracking with underlying stability problems.
Combined Transverse and Longitudinal cracking.
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SURFACE OPENINGS
Patching
A patch is an area of pavement which has been replaced with new material to repair the original
pavement. This indicates a pavement defect or utility cut excavation which has been repaired.
Patches with cracking, settlement or distortions indicate underlying causes still remain. Patches may
be in good condition and performing satisfactorily, moderately deteriorating or badly deteriorating
with other defects in the patched area and in need of replacement.
Typical patching repair of utility excavation.
Large patching in reasonably good condition.

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SURFACE OPENINGS
Patching
Extensive patching in very poor condition.
Very Poor/failed Patching with potholes and structural distress evident.

Issue 1, Rev. 1, Nov. 2013 21
SURFACE OPENINGS
Potholes
Potholes are bowl-shaped depressions where part of the pavement has been removed, exposing
the underlying layer(s). They are produced when cracking or some other defect allows moisture to
penetrate the pavement surface, which is subjected to repeated traffic loading. This results in
disintegration of the surface and the progressive removal of the underlying material. This is often
combined with poor drainage. Repair by excavating or rebuilding localised potholes as well as
localised surface dressing/overlay of repaired areas. Reconstruction required for extensive defects.
Large isolated pothole, extends through base. Note adjacent alligator cracks which
commonly deteriorate into potholes.
Reoccuring potholes due to poor patching work.
Issue 1, Rev. 1, Nov. 2013 22

SURFACE OPENINGS
Road Disintegration
Road disintegration is identified in two primary forms;
 Loss of road surface resulting in unbound surfacing materials (gravel or stone).
 Breakup of road into craters with less than 50% of the road width available to road
traffic. The road is no longer passable at speeds above walking pace.
Road not passable by vehicles at speeds above walking pace. Damage to vehicle may occur.
Disintegration of road resulting in exposure of subbase materials.
Issue 1, Rev. 1, Nov. 2013 23

Section 3: Rating Pavement Condition

Table 1 on the following page outlines the PSCI rating system for rating pavement condition. With
an understanding of surface defects, structural distresses and other pavement defects, you can
evaluate and rate flexible pavement surfaces. Surface defects comprise ravelling and bleeding;
Structural distresses (i.e. load-related) include rutting, alligator cracking, edge cracking and
breakup, potholes, poor/failed patching and road disintegration; while Other pavement defects
include other cracking (longitudinal, transverse reflection and slippage cracking), good/fair patching
and surface distortion.
The PSCI rating scale ranges from 10 for a pavement in excellent condition to 1 for a pavement in
failed condition. Most pavements will deteriorate through the phases listed in the rating scale. The
time it takes to go from excellent condition (10) to complete failure (1) depends largely on the
quality of the original construction and the amount of heavy traffic loading.
Once significant deterioration begins, it is common to see the pavement decline rapidly. This is
usually due to a combination of loading and the effects of additional moisture. As a pavement ages
and additional cracking develops, more moisture can enter the pavement and accelerate the rate of
deterioration.
Look at the photographs in this section to become familiar with the descriptions of the individual
rating categories. To evaluate an individual pavement segment, first determine its general
condition. Is it relatively new, toward the top end of the scale? Is it in very poor condition and at the
bottom of the scale? Or somewhere in-between?
Finally, review the individual pavement distresses and using the primary rating indicators and
secondary rating indicators given in Table 1, select the appropriate PSCI surface rating category for
the pavement segment.
Individual pavements will not have all of the types of distress listed for any particular rating. They
may have only one or two types.
Issue 1, Rev. 1, Nov. 2013 24

Table 1: The PSCI Rating System
Overall
Primary Rating Secondary Rating
PSCI
Rating Indicators* Indicators*
No Visible Defects.
10
Road surface in perfect condition.
Minor Surface Defects1.

9 Ravelling or Bleeding <10%. Road surface in very good condition.
Moderate Surface Defects1.

8 Ravelling or Bleeding 10% to 30%. Little or No Other defects.
Extensive Surface Defects1. Little or No Other defects.

7 Ravelling or Bleeding > 30%.
Old surface with aged appearance.
Moderate Other Pavement Defects2.

Other Cracking < 20%.
6 Patching generally in Good condition.
Surface Distortion requiring some reduction in speed.
Surface defects1 may be present.
No structural distress3.
Significant Other Pavement Defects2.

Other Cracking > 20%. Surface defects1 may be present.
5 Patching in Fair condition.
Surface Distortion requiring reduction in speed.
Very localised structural distress3
(< 5 m2 or a few isolated potholes).
Structural Distress3 Present.

Rutting, Alligator Cracking or Poor Patching for 5% to 25%.
4 Short lengths of Edge Breakup/Cracking. Other defects may be present.
Frequent Potholes.
Significant Areas of Structural Distress3.

Rutting, Alligator Cracking or Poor Patching for 25% to 50%.
3 Continuous lengths with Edge Breakup/Cracking. Other defects may be present.
More frequent Potholes.
Large Areas of Structural Distress3.

Rutting, Alligator Cracking or Very Poor Patching for > 50%.
2 Severe Rutting (> 75mm). Very difficult to drive on.
Extensive Very Poor Patching. Many Potholes.
Extensive Structural Distress3.
1 Road Disintegration of surface. Pavement Failure.

Many large and deep Potholes.
Severe Deterioration.
Virtually undriveable.
Extensive Failed Patching.
* Individual pavements will not have all the types of distress listed for any particular rating.
They may have only one or two types.
Note 1: Surface Defects = Ravelling or Bleeding.

Note 2: Other Pavement Defects = Other Cracking (longitudinal, transverse, reflection or slippage), Surface Distortion (Shape problems,
depressions/sags, shoving, bumps, settlement or heave), Good/Fair Patching.
Note 3: Structural Distress = Load-related defects comprising Rutting, Alligator Cracking, Edge Breakup/Cracking, Poor/Failed Patching, Potholes or Road
Disintegration.
Issue 1, Rev. 1, Nov. 2013 25

Rating 10
10
Excellent – Routine Maintenance
Newly constructed or recently overlaid roads are in excellent condition and require routine maintenance.
Rating 10: Road with no visible pavement defects.
Rating 10: New overlay, local road, no defects.
Issue 1, Rev. 1, Nov. 2013 26

Rating 9 9
Very Good – Routine Maintenance
Pavements in very good condition with very few visible defects. Newly surface dressed pavements.
Less than 10% of surface with surface defects (ravelling and bleeding). No other defects.
Rating 9: Road recently surfaced, good shape, little or no visible distresses.
Rating 9: Road recently surfaced with some minor loss of chippings.
Issue 1, Rev. 1, Nov. 2013 27

Rating 9: Recent surface dressing with some minor bleeding.
Issue 1, Rev. 1, Nov. 2013 28

Rating 8 8
Good – Restoration of Skid Resistance
This category includes roads which are showing surface defects (ravelling and bleeding) only. Roads
with 10 to 30% of surface with surface defects. Little or No Other defects present: No structural
distresses (rutting, alligator cracking, edge problems, potholes); No patching and No other cracking.
Road shape is very good.
Rating 8: Ravelling, 10% to 30% of surface.
Rating 8: Significant Bleeding, 10% to 30% of surface, note shine off dry road.
Issue 1, Rev. 1, Nov. 2013 29

Rating 7 7
Good - Restoration of Skid Resistance
Greater than 30% of surface with surface defects (ravelling or bleeding). Little or No Other defects:
No structural distresses (rutting, alligator cracking, edge problems, potholes); No patching; No
other cracking present, and road shape is good. This category also includes old roads with aged
appearance that need a surface dressing to maintain or restore waterproofing of the pavement
surface.
Rating 7: Extensive Ravelling (> 30%) over most of pavement surface.
Rating 7: Extensive Bleeding (> 30%) over most of pavement surface.
Issue 1, Rev. 1, Nov. 2013 30

Rating 7: Bleeding on greater than 30% of pavement surface.
Rating 7: Old surface, Ravelling > 30% and aged appearance.
Issue 1, Rev. 1, Nov. 2013 31

Rating 7: Old surface with some ravelling and aged appearance.
Issue 1, Rev. 1, Nov. 2013 32

Rating 6 6
Fair – Surface Restoration
Small quantities (< 20%) of other cracking (longitudinal, transverse, reflection, or slippage) may be
present. Patching present, generally in good condition. Pavement may be out of shape with some surface
distortion present requiring some reduction in driver speed necessary to maintain driver and passenger
comfort. Surface defects (ravelling and bleeding) may be present. No structural distresses present
(rutting, alligator cracking, edge problems, poor/failed patching or potholes). Localised repair needed
before surfacing.
Rating 6: Pavement surface distortion, transverse cracking at regular intervals.
Rating 6: Pavement surface distortion requiring reduction in driver speed, surface defects also present.
Issue 1, Rev. 1, Nov. 2013 33

Rating 6: Transverse cracking, weak support.
Rating 6: Old surface, surface seal is clearly broken due to transverse cracking, moisture can penetrate the
surface. Road in need of surface restoration to restore shape and waterproofing surface layer.
Issue 1, Rev. 1, Nov. 2013 34

Rating 5 5
Fair – Surface Restoration
Frequent other cracking present (> 20% of surface). Patching present generally in fair condition. Pavement
out of shape with significant surface distortions requiring driver to reduce speed. Some very localised
structural distress (rutting, alligator cracking, edge problems, poor/failed patching or potholes) may be
present in small quantities (< 5 sq.m of surface or a few isolated potholes). Surface defects (ravelling and
bleeding) may be present. The road requires either large quantities of localised repair before surfacing or
the road is clearly in need of reshaping with significant driver discomfort.
Rating 5: Loss of Shape, localised repair needed, patching in fair condition.
Rating 5: Surface distortion, transverse cracking, some localised structural distresses.
Issue 1, Rev. 1, Nov. 2013 35

Rating 5: Extensive Longitudinal and Transverse Cracking, pumping of fines from under surface.
Issue 1, Rev. 1, Nov. 2013 36

Rating 4 4
Poor – Structural Overlay
Road shows signs of needing strengthening by structural overlay. Structural distresses are present
(rutting, edge problems, alligator cracking, poor/failed patching or potholes). Rutting, alligator cracking
or poor patching present (5% to 25% of surface). Short lengths of edge breakup/cracking present. Fre-
quent potholes present. Other defects (ravelling, bleeding, surface distortion or other cracking) may be
present.
Rating 4: Rutting, potholes and patching in wheelpath. Structural distresses are clear.
Rating 4: Edge problems, rutting, out of shape and other defects present.
Issue 1, Rev. 1, Nov. 2013 37

Rating 4: Alligator cracking, rutting, and potholes present.
Rating 4: Alligator cracking, rutting and pothole formation in wheelpath. Structural distresses are clear.
Issue 1, Rev. 1, Nov. 2013 38

Rating 3 3
Poor – Structural Overlay
Significant quantities of structural distress present (rutting, edge problems, alligator cracking, poor/failed
patching or potholes). Rutting, alligator cracking or poor patching present (25% to 50% of surface). Signifi-
cant continuous lengths with edge breakup/cracking and loss of material at edges. More frequent pot-
holes. Other defects may be present. Structural overlay required to strengthen road.
Rating 3: Significant alligator cracking over large areas, some potholes and edge problems.
Rating 3: Extensive alligator cracking and structural distress.
Issue 1, Rev. 1, Nov. 2013 39

Rating 3: Significant alligator cracking and structural problems over large areas.
Rating 3: Edge problems/cracking, alligator cracking, rutting and potholes.
Issue 1, Rev. 1, Nov. 2013 40

Rating 2 2
Very Poor – Road Reconstruction
Roads are severely deteriorated and need reconstruction. Very significant quantities of alligator
cracking, rutting or very poor patching present (over 50% of surface). Severe rutting (over 75 mm deep).
Extensive patching in very poor condition. Many potholes. Very difficult to drive on. Road needs full depth
reconstruction with extensive base repair.
Rating 2: Severely deteriorated, extensive patching and structural problems , loss of surfacing in places.
Rating 2: Failed areas, extensive patching in very poor condition, loss of surfacing in places.
Issue 1, Rev. 1, Nov. 2013 41

Rating 1 1
Failed – Road Reconstruction
Road layers have completely failed. Severe structural distress with extensive loss of pavement surface.
Many large and deep potholes, patching in failed condition. Severe deterioration and virtually undrive-
able. Road needs full depth reconstruction with extensive base repair.
Rating 1: Entire width of road disintegrated with reconstruction required.
Rating 1: Road surface disintegrated, extensive road failure.
Issue 1, Rev. 1, Nov. 2013 42

Rating 1: Significant loss of pavement surface, extensive road failure.
Rating 1: Significant loss of pavement surface, Large quantities of severe potholes.
Issue 1, Rev. 1, Nov. 2013 43

Section 4: Practical Advice on Rating Roads
Inventory and Field Inspection

Most agencies routinely observe roadway conditions as a part of their normal work and travel. However,
a road network inspection means looking at the entire roadway system as a whole and preparing a
written summary of conditions. This inspection has many benefits over casual observations. It can be
helpful to compare segments, and rating decisions are likely to be more consistent because the roadway
system is considered as a whole within a relatively short time.
Having a written record and objective information also improves your credibility with the public. Finally
a written inventory is very useful in documenting changing roadway conditions. Without records over
several years it is impossible to know if road conditions are improving, holding their own, or declining.
Annual budgets and long range planning are best done when based on actual needs as documented with
a written inventory.
Averaging and Comparing Sections

For evaluation, divide the local road system into individual segments which are similar in construction
and condition. Obviously, no roadway segment is entirely consistent. Also, surfaces in one section will
not have all of the types of distress listed for any particular rating. They may have only one or two types.
Therefore, some averaging is necessary.
The condition of the full width of the road should be rated. The objective is to rate the condition that
represents the majority of the roadway. Small or isolated conditions should not influence the rating.
Occasionally surface conditions vary significantly within a short length along the road segment. For
example, short sections of good condition may be followed by sections of poor surface conditions. In
these cases, it is best to rate the segment according to the worst conditions. It is not necessary to keep
track of all changes in road condition if the condition is varying over very short lengths. As a rough guide,
a length of at least 200metres is required to justify recording a change in road condition rating category.
The overall purpose of condition rating is to be able to compare each segment relative to all the other
segments in your roadway system. On completion you should be able to look at any two pavement
segments and find that the better surface has a higher rating.
Within a given PSCI rating, say 6, not all pavements will be exactly the same. However, they should all be
considered to be in better condition than those with lower PSCI ratings, say 5. Sometimes it is helpful in
rating a difficult segment to compare it to other previously rated segments. For example, if it is better
than one you rated 5 and worse than a typical 7, then a rating of 6 is appropriate. Having all pavement
segments rated in the proper relative order is most important and useful.
Issue 1, Rev. 1, Nov. 2013 44

Section 5: Conclusions and Next Steps
Using local road funds most efficiently requires good planning and accurate identification of appropriate
rehabilitation projects. Assessing roadway conditions is an essential first step in this process. The
Pavement Surface Condition Index (PSCI) rating system in this Rural Flexible Roads Manual has been
developed to improve the data collection and quality of visual surveying of non-national roads, and to
improve decision making and use of road maintenance funds more efficiently. It can be used directly by
local authority officials and staff in the Republic of Ireland. It may be combined with additional
pavement testing and data collection in a more comprehensive pavement management system in
planning future budgets and priorities.
The PSCI rating system is based only on visual pavement defects. The impact of surface-related defects,
structural-related defects and other defects is identified when applying the overall PSCI rating. The
results of the rating system should be relatable to the maintenance treatment categories specified for
use on Non-National roads by the Department of Transport, Tourism and Sport. Table 2 on the following
page summarises the overall relationships between these factors.
Issue 1, Rev. 1, Nov. 2013 45

Table 2: Treatment Measures
Structure
Overall
Surface
PSCI Treatment Measures
Rating
Excellent
10 Routine
Maintenance
Good
Very
8
Fair
Resealing &
Good
Restoration of Skid Resistance
7
Poor
Surface
6
Fair
Restoration
–
Fair
Carry out localised repairs
5
Poor
and treat with surface treatment or thin overlay.
Structural
4 Overlay Overall
Poor
-
3 Required to strengthen road.
Localised patching and repairs required prior to overlay.
Overall
2
Poor
Very
Road Reconstruction
-
Overall
1
Failed
Needs full depth reconstruction with extensive base repair.
Issue 1, Rev. 1, Nov. 2013 46

Section 6: Bibliography
1. PASER Asphalt Roads Manual, Wisconsin Transportation Information Center, University of

Wisconsin-Madison (2002).
2. Non-National Road Pavement Condition Study, Distress Catalogue Descriptions and Rating
Procedures (2004).
Issue 1, Rev. 1, Nov. 2013 47

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Volume 1 of 3

Rural Flexible Roads Manual

DOCUMENT CONTROL SHEET

Client Department of Transport, Tourism and Sport

Author PMS Pavement Management Services Ltd.

Document Title Rural Flexible Roads Manual

Document No. Issue 1, Rev. 1, November 2013

This Document DCS TOC Text Tables Figures Appendices

Rev. Status Author(s) Reviewed By Office of Origin Issue Date

Rev. 0 Final Issue B. Mulry K. Feighan Galway 20 Apr 12

Rev. 1 Final Issue B. Mulry K. Feighan Galway 04 Nov 13

Issue 1, Rev. 1, Nov. 2013 1

Issue 1, Rev. 1, Nov. 2013 2

Pavement Deformation ............................................................................................................... 10

Section 3: Rating Pavement Condition.................................................................................. 24

Section 4: Practical Advice on Rating Roads.......................................................................... 44

Section 5: Conclusions and Next Steps .................................................................................. 45

Section 6: Bibliography ........................................................................................................47

Issue 1, Rev. 1, Nov. 2013 3

1. Inventory all local roads.

2. Periodically evaluate the condition of all pavements.

Issue 1, Rev. 1, Nov. 2013 4

Section 2: Pavement Distress – Flexible Pavements

Deterioration has three general modes. These are

Issue 1, Rev. 1, Nov. 2013 5

Moderate Ravelling evident in wheelpaths.

Issue 1, Rev. 1, Nov. 2013 7

Bleeding/Fatting-up of binder needs repair.

Bleeding. Dark, shiny areas extending along the wheelpaths.

Issue 1, Rev. 1, Nov. 2013 9

Severe Rutting over 50mm in depth evident in wheel path.

Severe Rutting caused by poor base or subgrade problems.

Issue 1, Rev. 1, Nov. 2013 10

Significant depression visible in concentrated area.

Depression in subsided area.

Issue 1, Rev. 1, Nov. 2013 11

Surface Distortion (note road marking on left edge).

Issue 1, Rev. 1, Nov. 2013 12

Alligator cracking may comprise;

 A pattern of parallel and interconnecting cracks that may be lightly spalled.

Issue 1, Rev. 1, Nov. 2013 13

Wide area of alligator cracking.

Issue 1, Rev. 1, Nov. 2013 14

Edge Breakup identified by cracking at the edge of the road pavement.

Issue 1, Rev. 1, Nov. 2013 15

Edge Breakup at the edge of the road pavement.

Issue 1, Rev. 1, Nov. 2013 16

Multiple cracking within 300 mm of the pavement edge.

Potholes and loss of pavement material along the pavement edge.

Issue 1, Rev. 1, Nov. 2013 17

Regular pattern of transverse cracking – bleeding also evident in the wheelpaths.

Issue 1, Rev. 1, Nov. 2013 18

Slippage cracking with underlying stability problems.

Combined Transverse and Longitudinal cracking.

Issue 1, Rev. 1, Nov. 2013 19

Typical patching repair of utility excavation.

Large patching in reasonably good condition.

Extensive patching in very poor condition.