HomeMy WebLinkAboutAgenda Work Session 12-11-07Z:\Council Packets\2007\WS12-11-07\Agenda Work Session 12-11-07.doc Last Printed 12/7/2007 1:51:43 PM
NOTICE OF THE
WORK STUDY SESSION OF
THE FOUNTAIN HILLS TOWN COUNCIL
Mayor Wally Nichols
Councilmember Mike Archambault Councilmember Keith McMahan
Vice Mayor Ginny Dickey Councilmember Henry Leger
Councilmember Ed Kehe Councilmember Jay Schlum
TIME: 5:00 P.M. – 7:00 P.M.
WHEN: TUESDAY, DECEMBER 11, 2007
WHERE: FOUNTAIN HILLS COUNCIL CHAMBERS
16705 E. AVENUE OF THE FOUNTAINS, FOUNTAIN HILLS, AZ
ALL WORK-STUDY ITEMS LISTED ARE FOR DISCUSSION ONLY. NO ACTION CAN OR WILL BE TAKEN.
The primary purpose of work session meetings is to provide the Town Council with the opportunity for in-depth discussion and
study of specific subjects. Public comment is not provided for on the Agenda and may be made only as approved by consensus
of the Council. In appropriate circumstances, a brief presentation may be permitted by a member of the public or another
interested party on an Agenda item if invited by the Mayor or the Town Manager to do so. The Presiding Officer may limit or
end the time for such presentations.
WORK STUDY AGENDA
1.) CALL TO ORDER AND ROLL CALL – Mayor Nichols
2.) PRESENTATION AND DISCUSSION of the 2007 Pavement Management Report by Stantec
Consulting.
3.) ADJOURNMENT.
DATED this 7th day of December, 2007.
Bevelyn J. Bender, Town Clerk
The Town of Fountain Hills endeavors to make all public meetings accessible to persons with disabilities. Please call 837-2003 (voice) or 1-800-367-8939
(TDD) 48 hours prior to the meeting to request a reasonable accommodation to attend this meeting or to obtain agenda information in large print format.
Supporting documentation and staff reports furnished the council with this agenda are available for review in the Clerk’s office.
#286
Kingstree Blvd @ Mangrum Court (looking west)
#287
Kingstree @ Mangrum Court (looking east)
#288
Saguaro Blvd.@ Pepperwood Dr.(looking south)
#290
Malta Dr. @ Rand Dr. (looking west)
#291
Appian Way @Trevino Dr. (looking south)
#292
FH Blvd @ Ironwood Dr. (looking north)
#295
Sunridge Dr. @Cactus Flower Way (looking north)
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Stantec Consulting | Infrastructure Management
8211 South 48th Street | Phoenix, AZ 85044
T 800-827-5870 | F 602 431 9562
| www.stantec.com
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
EXECUTIVE SUMMARY
November 11, 2007
\Fhills\final\Report\FHills Pavement Present Status Report KHv5.doc E.1
Executive Summary
INTRODUCTION
Infrastructure strategic planning is an essential component in the management of public facilities
and is driven by aging infrastructure, population growth and the current reality of dwindling
budgets for maintenance management. The emphasis is now being placed on not only knowing
the true cost of providing services to the public today, but also understanding what will be
required to maintain a certain level of services throughout the life of the asset. In other words,
we are moving to sustainable management.
OBJECTIVES
The Town of Fountain Hills retained Stantec Consulting to perform an update of the Town’s
Pavement Management System. The goals of the evaluation will be used to determine:
• The overall performance of the Town’s pavement network in order to provide
recommended rehabilitation strategies to improve the condition of the Town’s streets
Ultimately, the successful completion of this project will allow Town staff to:
• Assess/review the current condition of any pavement section,
• Predict the future conditions for various budget and service levels, which help:
⇒ identify funding needs and shortfalls
⇒ build support for increased funding
⇒ flag potential performance concerns
• Set criteria for applying various maintenance and rehabilitation strategies for each
pavement section,
• Calculate costs associated with each maintenance/rehabilitation strategy,
• Specify various appropriate budget scenarios, and
• Prioritize all maintenance and rehabilitation work on a network-wide basis, based on
previously specified budget restraints.
Pavement management is not just a set of procedures; it is, in fact, a philosophy that requires a
significant change in organizational culture both at the community and political level. This
change will not occur overnight; however, the Pavement Management Report will provide Town
staff with a series of important tools, which can be used to begin the education and
communication process. Without taking this necessary action, streets will continue to
deteriorate and wear out creating an extremely greater cost to the community in upcoming
years.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
EXECUTIVE SUMMARY
November 11, 2007
\Fhills\final\Report\FHills Pavement Present Status Report KHv5.doc E.2
What is it worth?
Q2
What condition
is it in?
Q3
What do we
need to do to it?
Q4
How much
money do we need?
Q6
Questions of
Sustainable Asset
Management
What do we have?
Q1
When do we
need to do it?
Q5
What is it worth?
Q2Q2
What condition
is it in?
Q3Q3
What do we
need to do to it?
Q4Q4
How much
money do we need?
Q6Q6
Questions of
Sustainable Asset
Management
What do we have?
Q1Q1
When do we
need to do it?
Q5Q5
Sustainable Asset
Management Activities
Determine
System Value
Determine
Asset Condition
Develop O&M and
Capital Work Projects
Develop & Analyze
Life Cycle Cost Profile
Develop
System Inventory
Prioritize & Determine
Work Schedule
Sustainable Asset
Management Activities
Determine
System Value
Determine
Asset Condition
Develop O&M and
Capital Work Projects
Develop & Analyze
Life Cycle Cost Profile
Develop
System Inventory
Prioritize & Determine
Work Schedule
How will we
fund it?
Q7
Develop Sustainable
Funding Model
How will we
fund it?
Q7Q7
Develop Sustainable
Funding Model
This report is based on a blend of the Town’s own policies, the format used by the American
Society of Civil Engineers (ASCE) in assessing pavement infrastructure; the best practices
developed by the National Infrastructure Guide of Canada as well as a number of other local
municipal agencies.
Basic Principles Approach
Our approach is firmly grounded in the principles of
sustainable asset management and is based upon seven
fundamental questions illustrated in the diagram on the
right. Though this assignment only required the first few
of these questions these are steps taken to assist the
Town in moving forward with these principals to sustain
its asset infrastructure. These questions are:
1. What do you have and where is it? (Inventory)
2. What is it worth? (Costs/replacement Rates)
3. What is its condition and expected remaining
service life? (Condition and Capability Analysis)
4. What is the level of service expectation, and
what needs to be done? (Capital and Operating
Plans)
5. When do you need to do it? (Capital and
Operating Plans)
6. How much will it cost and what is the acceptable
level of risk(s)? (Short- and Long-term Financial
Plan identified by Town Staff)
7. How do you ensure long-term affordability?
(Short- and Long-term Plan resulting from the
study)
This report and associated recommendations will provide the basis for defining the way towards
answering all of these questions.
OVERVIEW OF FINDINGS
The Town of Fountain Hills has current overall replacement value of $146 million of street
infrastructure assets. See summary in Table E 1on the following page.
The total cost of immediately required repairs and refurbishments is also included that will bring
the assets to an acceptable levels of service. See summary in Table E 2 the following page.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
EXECUTIVE SUMMARY
November 11, 2007
Fhills\final\Report\FHills Pavement Present Status Report KHv5.doc E.3
Table E 1: Pavement Replacement Value
Asset Type Inventory 2007 Replacement
Value
Street Network 395 lane miles $145,452,912
Table E 2: Current Reinvestment Needs (Backlog) All Asset Categories
Asset Type Asset Component Inventory
Bring up to
Acceptable Level
of Service
Streets Pavement Network 395 lane miles $8,865,878
2007 Total Backlog $8,865,878
Table E 3 below illustrates the overall rating or network condition score for the pavement
networks. The network score varies between zero (0) and one hundred (100), with 0
representing the poorest possible condition and 100 representing the best possible ranking.
Table E 3: Network Condition Score
Asset Type Asset Component Score
0 - 100
Streets Overall Rating 69
During the pavement management system analyses, pavement performance models were used
to estimate the rehabilitation requirements of the Town’s street network for a ten-year period
beginning in 2007. By setting a minimal “acceptable” level of service of pavement quality along
with using Town supplied traffic volumes and estimated construction and sub-grade properties;
each evaluated street segment was analyzed to determine when it would be come in need of
repair and the type of repair that would be warranted. As a result of this analyses, it was
determined that up to 45 percent of the Town’s street network is in need of some form of
maintenance or repair in 2007, with an estimated cost of $8.9 million.
In general, the results indicate that the Town’s current processes and budgets are maintaining
the streets at a reasonable level of service when compared to other growing municipalities
regarding overall pavement performance. However, given the current age of the Town’s
infrastructure and continuing rising cost of construction, is not uncommon to see an
accumulated build up of rehabilitation projects. Having said this, it is imperative the Town
continue its efforts at cost effectively reducing the current backlog of poor streets and
performing a more aggressive routine and preventative maintenance on those streets currently
in good condition.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
TABLE OF CONTENTS
November 11,, 2007
FHills Pavement Present Status Report KHv5.doc i
Table of Contents
EXECUTIVE SUMMARY E.1
INTRODUCTION ..........................................................................................................................1
OBJECTIVES................................................................................................................................1
Basic Principles Approach.....................................................................................................2
OVERVIEW OF FINDINGS ..........................................................................................................2
1. STREETS 2
INTRODUCTION ..........................................................................................................................2
WHAT DO WE HAVE? .................................................................................................................2
WHAT IS IT WORTH? ..................................................................................................................3
WHAT CONDITION IS IT IN?.......................................................................................................4
Surface Distress Index (SDI) .................................................................................................4
Riding Comfort Index.............................................................................................................6
Pavement Quality Index.........................................................................................................8
Specific Conditions ................................................................................................................9
WHAT DO WE NEED TO DO?...................................................................................................10
WHEN DO WE NEED TO DO IT? ..............................................................................................11
Minimal Acceptable Levels of Pavement Performance........................................................12
HOW MUCH MONEY DO WE NEED?.......................................................................................14
Scenario 1 - Planned Budget...............................................................................................15
Scenario 2 - Do Nothing.......................................................................................................15
Scenario 3 - Unconstrained “Need Driven” Budget..............................................................15
Discussion of Results...........................................................................................................16
HOW DO WE ENSURE LONG-TERM AFFORDABILITY? ........................................................18
RECOMMENDATIONS...............................................................................................................18
FUTURE PAVEMENT MANAGEMENT STRATEGY .................................................................20
APPENDIX A~ PAVEMENTS ~ STREET LISTING AND NEEDS ASSESSMENT A
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 2
1. Streets
INTRODUCTION
The Town of Fountain Hills street network currently consists of 395 lane miles of pavement
spanning different traffic functional classes. The pavement condition update recently
conducted by Stantec determines the overall performance of the Town’s pavement network
in order to provide recommended rehabilitation strategies to improve the condition of the
Town’s streets.
WHAT DO WE HAVE?
The street network that serves the Town consists of a series of asset components ranging by
traffic functions from local residential to major arterial thoroughfares. The data used to
compile the pavement inventory was extracted from the Town’s Geographical Information
System (GIS) and the pavement management system databases. These components have
been identified in Table1 below:
Table1: Pavement Network Database Statistics
Major Arterial Roadways:
Major arterials roadways are high traffic volume, full access-control roads with intersection
spacing dictated either by designated major highways or by key access points located on
other inter-regional facilities.
Asset
Component Traffic Volumes
Street
Segment
Count
Network
Street
Mileage
Network
Lane
Mileage
Functional Class
Average Annual
Daily Traffic
(traffic count - high/low ranges)
# mi mi
Alleys 25-50 24 3.2 6.4
Local Street 200 – 1000 919 98.6 198.3
Minor Collector 1000 – 3000 129 14.1 28.2
Major Collector 3000 -7500 230 28.5 82.4
Minor Arterial 7500 – 15000 192 26.6 59.6
Major Arterial 10000 20000 16 7.9 19.5
Total Pavement
Network
1510 178.9 394.4
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 3
Minor Arterial Roadways:
Minor arterial roadways are moderate traffic volume, full or partial access control roads that
provide service to retail, commercial and industrial land uses. Minor arterial roadways may
develop into principal arterials if traffic volumes increase due to an increase in area
development.
Major Collector Roadways:
Major collector roadways carry a relatively high volume of traffic within larger neighborhoods
and can accommodate the traffic volumes generated by minor retail and other commercial
services. These streets are intended to provide convenient traffic movement and access to
the arterial roadways.
Minor Collector Roadways:
Minor collector roadways, identified by wide travel lanes, provide access to larger cul-de-sac
subdivisions. Developers may use this roadway classification, at Town Council discretion, to
provide single access for up to 90 dwelling units without need for a secondary access road.
Note: A full description of the traffic functional classification of streets is specified in the Town’s
general plan.
WHAT IS IT WORTH?
The estimated replacement value of the street network and associated appurtenances,
based upon current dollar value (2007) is $146 million. Table 2 and associated Pie Chart
provide a breakdown of the contribution of each of the network components to the overall
system value:
Table 2: Pavement Network Replacement Value
Asset Component Quantity
2007
Replacement
Cost *
Replacement
Value
Pavement type sq feet $ / sq ft $
Flexible Asphalt 30,302,690 $ 4.80 $145,452,912
Total Pavement Network 30,302,690 $145,452,912
*Note: The replacement costs were measured by construction costs + 20% allocated for overhead.
Overhead includes; engineering services, contingency, and administration costs along with cost
allocations (to other departments). These must be considered when setting budget plans, both in
terms of operating as well as capital improvements.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 4
Pie Chart 3: Street Network by Functional Classification
Local Street
50%
Minor Collector
7%
Major Collector
21%
Minor Arterial
15%
Major Arterial
5%Alleys
2%
As can be seen from the pie chart above, the Town’s Local streets make up 50% of the
pavement system.
WHAT CONDITION IS IT IN?
The overall condition can also be termed as “present status”. The present status component
of the pavement management software is extremely important in that it readily provides
useful data to the user and provides the base necessary for subsequent analysis. The
objective of the present status analysis is to provide updated performance information on the
complete pavement network broken down by functional class, and as a whole, allows the
Town to evaluate:
• The deterioration of streets as determined by the performance indicators; and,
• The overall change in the network performance indicator distributions over time.
Surface Distress Index (SDI)
The surface condition of a street is rated in terms of the type, severity, and extent of
pavement distresses present at the time of the survey. The severity reflects how bad the
problem is, and is rated in three categories as; slight, moderate or severe. For example,
map, longitudinal and transverse cracking are rated as follows:
1. Slight, if cracks less than ½” wide
2. Moderate, if cracks are between ½” and 1” in width
3. Severe, if cracks are wider than 1”
The extent refers to how much of the pavement is affected by a distress for each severity.
The following distresses itemized in Table 4 were rated for flexible pavements:
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 5
Table 4: Surface Condition Distresses
The extent and severity of each distress type that are present on the streets are combined
using different weighting factors to generate a Surface Distress Index (SDI) for each
pavement section. These ratings can range from “0” to “100”. A value of “100” indicates that
the surface of the street section is free of distress and a value of “0” indicates that the
surface is severely distressed. An SDI value of 70-75 generally marks the point at which the
distresses are becoming significant.
A plot showing the SDI distribution for 2007 is shown in Table 5. The network mean SDI for
Fountain Hills is 79. Generally speaking the majority of the network is in “good” condition.
The plot also shows that 56.5 percent of the network has SDI scores in the 80-100 range,
which indices that these pavements have little or no distress. This is indicative of the
moderately aggressive routine maintenance program the Town has been successful in
implementing. Approximately 29 percent of the network has an SDI score less than 70,
which indicates that the pavement is beginning to deteriorate at a faster rate.
Table 5: Performance Indicators Surface Distress Index (SDI) by lane miles
Patching Edge Cracking
Rippling/Shoving Alligator Cracking
Raveling/Streaking Potholes
Bleeding/Flushing Map Cracking
Distortion Longitudinal/ Transverse Cracking
Excessive Crown Wheel track Rutting
Below 70
distresses become significant
Below 70
distresses become significant
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 6
The 2007 summarized distress listing for the entire street network is presented in Appendix A
Riding Comfort Index
Roughness of the pavement is measured in a longitudinal profile calculated electrically by
sensors mounted on the front bumper of Stantec’s Road Tester (RT3000) data collection
vehicle. Roughness measurements are correlated to an assessment of ride quality. This
subjective assessment is termed the Riding Comfort Index (RCI). The resulting RCI values
can range from 0 to 100 in value. A value of 80 to 100 indicates an extremely smooth ride
and a value of 0 to 20 indicates an extremely rough ride. These extreme values (100 and 0),
however, are generally unachievable. Ride values of 60 to 80 are measured as “good”.
Values in the 40 to 60 range often indicate a pavement that is “fair” and soon becoming in
need of rehabilitation such as an overlay. Finally, RCI values in the 0 to 40 range are
indicative of pavements in “poor” to “very poor” condition. The network average RCI for the
Fountain Hills network is 71 which indicate that much of the network exhibits a “good” riding
comfort. Table 6 below, illustrates a standard roughness scale published by the American
Association of State Highway and Transportation Officials (AASHTO)
Table 6: Standard AASHTO Roughness Rating Scale
80 - 100
0 - 20
Poor ride quality is the first indication to the public that the streets are in need of repair. The
rougher the streets the more stress traffic has on its roadways, not to mention the wear and
tear on the vehicles. This causes the public to repair their vehicles sooner than expected as
well as further premature failure to the Towns streets. The Ride Comfort Index (RCI)
distribution for 2007 is shown in Table 7, on the following page. Pavements with RCI values
in the range of 40 to 60 are considered to have marginal ride quality characteristics. The plot
shows roughly only 46 lane miles, or 11.8 percent of the Fountain Hills pavement network,
fall into this category. Approximately 342 lane miles, or 88.1 percent of this network have
RCI values greater than 60, which is indicative of “good” ride characteristics.
Very poor20 -40
40 -60
60 -80
Very Poor
Poor
Fair
Good
Very Good
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 7
Table 7: Performance Indicators Ride Comfort Index (RCI) by lane miles
The 2007 Summarized Ride Comfort listing for the entire street network is presented in
Appendix A.
Structural Adequacy Index
The structural adequacy of a pavement indicates the pavement’s ability to carry expected
traffic loads while providing an acceptable level of service. The structural adequacy of a
pavement is determined by analyzing the measured deflection of the pavement under a
controlled loading condition and comparing this response to the maximum allowable
deflection associated with anticipated loading conditions.
The subgrade strength is a key function of the type of subgrade material supporting the
pavement. Subgrade strength is grouped into one of three general categories: ‘Strong’, ‘Fair’,
and ‘Weak’. This designation is used as a variable in long-term pavement performance
modeling, and can be used in the decision making process to identify feasible strategies for
pavement sections requiring rehabilitation.
Below 40
Poor Ride Comfort
Very GoodGoodFairPoorVery Poor
40
Below 40
Poor Ride Comfort
Very GoodGoodFairPoorVery Poor
40
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 8
Presently the Town’s pavement program is setup such that 100 percent of the sections in the
defined network are defaulted to a subgrade strength of ‘strong’. The basis behind this is that
Arizona soils provides good moisture content of native materials, density, and the local
drainage conditions of Fountain Hills provide reasonably good runoff. This is sufficient from
a network level study; however, the Town may want to consider updating the default
pavement structural data with actual information from existing and/or new information
sources to determine more accurate results.
Fountain Hills has a good mixture of adequate street base material to support various traffic
loads, however, there is a percentage of clay soils that exists within the Town. Therefore,
while subgrade values may be sufficient for residential streets, additional care must be taken
on collectors and arterial streets due to higher traffic loads and volumes.
Pavement Quality Index
The Pavement Quality Index (PQI) is used to provide a single overall assessment of
pavement quality. The PQI is based on one or more of the basic Performance Indicators -
the Surface Distress Index (SDI), the Riding Comfort Index (RCI) and the Structural
Adequacy Index (SAI).
One mathematical model for calculating the PQI was used in this study, PQI = f(SDI, RCI,
SAI). This model uses the SDI as the primary variable in conjunction with the RCI and SAI.
The PQI is adjusted downward for RCI scores less than 100. The magnitude of the
adjustment increases as the RCI score decreases. An adjustment is also made to account
for the degree of structural adequacy / inadequacy of the pavement as determined by the
SAI. The PQI is adjusted upward for structurally adequate pavements and downward for
structurally inadequate pavements.
As with the RCI, SAI and SDI, the PQI varies between zero (0) and one hundred (100), with
0 representing the poorest possible pavement, and 100 representing the best possible
pavement. See Table 8 for a standard condition rating scale: The custom scale is also
provided to illustrate a more simplistic view broken down into three basic categories. Typical
values for a newly constructed street range from 95 to 100. The PQI level at which a
pavement becomes in need of rehabilitation is typically in the 40 to 70 range, for lower traffic
volumes and 40 to 75 for streets with higher traffic volumes.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 9
Table 8: Standard Pavement Condition Rating Scale (PQI)
Specific Conditions
A plot showing the aged PQI distribution in 2007 for the entire network of the Town of
Fountain Hills is shown in Table 9 on the following page. The Town of Fountain Hills
pavement network mean aged PQI for 2007 is 69 and generally speaking is a network that is
in “good” condition. The plot illustrates that the Town’s street network is even distributed. A
PQI value less than 40 is indicative of a pavement providing an overall poor level of service.
Approximately 19 lane miles or 4.8 percent of the network is in this category. On the other
hand, the majority of the network 55.2 percent is in the “good” to “excellent” range (70 or
better) which is providing a good level of service to the Town.
Distress
Index
Structural
Index
Roughness
Index
Excellent
Failed
Very poor
Poor
Fair
Good
Very good
0
10
25
40
55
70
85
100
Unsatisfactory
Adequate
0
55
100
70
PQI
Standard PQI
Rating Scale
Custom PQI
Rating Scale
Distress
Index
Structural
Index
Roughness
Index
Excellent
Failed
Very poor
Poor
Fair
Good
Very good
0
10
25
40
55
70
85
100
Unsatisfactory
0
40
100
PQI
Standard PQIRating Scale Custom PQI Rating Scale
Degraded
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 10
Table 9: Performance Indicators Aged Pavement Quality Index (PQI) for 2007
The 2007 summarized pavement quality index listing for the entire pavement network is
presented in Appendix A and lists each individual section's PQI, RCI, and SDI by section.
WHAT DO WE NEED TO DO?
After a pavement section has been determined to be “in need” of rehabilitation, potential
rehabilitation alternatives can be generated. To achieve this goal, a list of potential
alternatives and some of their characteristics must be specified. This list should include all of
the rehabilitation alternatives the agency would consider to rectify a wide range of pavement
deficiencies for all pavement types in the network. In addition, to determine the return on
investment, a benefit level must be assigned to each rehabilitation alternative. This benefit
level allows the after rehabilitation PQI of the section to be estimated.
Stantec used a decision tree approach to determine the technically feasible rehabilitation
alternatives for each section. The basic philosophy behind this approach is to maximize
flexibility. In this regard, the decision trees are completely user defined to ensure that the
process accurately models the decision process employed by the agency. Decision trees
Below 70
Rehabilitation or repair is recommended
Below 70
Rehabilitation or repair is recommended
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 11
should exist for every combination of functional classification and pavement type to
accommodate potential differences in decision logic between the various combinations of
alternatives. Table 10 below, presents the rehabilitation strategies and associated unit costs
provided by Town personnel.
Table 10: Rehabilitation Alternatives (Base year 2007)
Description
Unit
Cost
$ /ft2
Thick.
Factor Benefit Level
After
Rehab
PQI
Treatment Trigger
Slurry Seal $0.23 0.1 1- Surface Treatment 88 Minor Maintenance
Micro Surfacing $0.26 0.1 1- Surface Treatment 88 Minor Maintenance
2” Edge Mill & Overlay $1.07 2.0 2- Edge Mill & O/L 96 Major Maintenance
2” Full Mill & Overlay $1.40 1.8 3- Full Mill & O/L 96 Major Maintenance
Reconstruct 3” AC / 6” AGB $4.80 9.0 5- Reconstruction 100 Rehabilitation
Note: It is recommended that a review of the defined alternative unit costs and base years be
periodically undertaken to ensure that the cost results produced by the pavement management
program are as accurate as possible.
The alternatives to be considered should be rehabilitation oriented and include such
treatments as overlay, mill and overlay, and reconstruction. General surface treatments such
as chip sealing and slurry sealing can also be specified, but items such as crack sealing and
skin patching, which are applied to localized areas within a section, are considered to be
routine maintenance activities and therefore should not be included in the rehabilitation
analysis.
WHEN DO WE NEED TO DO IT?
In order to estimate future rehabilitation requirements of a pavement network over a period of
time, the first step is to determine when a pavement section requires rehabilitation. As
pavements depreciate, the rate of decrease depends on many factors but it can be
demonstrated that these key factors include: the traffic loading conditions, subgrade strength
and the properties and thickness of the pavement structure layers. These factors have been
set up in the pavement management system based on information provided by Town
personnel and are used to prioritize the rehabilitation requirements for the network of
pavements over a period of time. This period of time, typically ten years, is known as the
programming period.
The Need Year of a pavement or when it requires rehabilitation is defined as the year in
which the value of the pavement drops to or below a predetermined service level or minimum
acceptable quality. Table 11 below shows typical pavement performance triggers and when
they occur with the combination of “thin” pavement thickness’, “medium” traffic volumes
(collector) and “strong” subgrade strength:
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 12
Table 11: Pavement Performance Triggers
Minimal Acceptable Levels of Pavement Performance
This minimum acceptable performance is measured using the PQI value. The minimum PQI
levels are selected to:
• Maintain/improve the existing level of service of the entire network
• Provide the system with sufficient backlog to drive the rehabilitation program
The minimum PQI levels (or PQI trigger levels), for the Town of Fountain Hills are set by
traffic functional classification. Typically the upper functional classification pavements have
PQI triggers set higher than the local functional classification pavements, reflecting the users
demand for higher levels of service on the upper functional classification streets. The
selection of the minimum PQI levels, for the Town of Fountain Hills , represents a ‘balance’
between maintaining the existing level of service and keeping the backlog manageable.
The current minimum acceptable PQI’s used by the Town are shown in Table 12 below.
The minimum acceptable PQI’s are entered on the top line of the decision tree process. The
minimum acceptable PQI’s can be represented by a horizontal line across the performance
curve models.
30
0
10
20
30
40
50
60
70
80
90
100
010 20
Minor
Maintenance
Rehabilitation
Replacement
Major
Maintenance
Thresholds Minor Maint
Thresholds Major Maint
Thresholds Rehabilitation
Thresholds Reconstruction
Time (years)
for Majors StreetsMinimal Acceptable PQI
Pavement Quality Index (PQI)AC Collectors
30
0
10
20
30
40
50
60
70
80
90
100
010 20
Minor
Maintenance
Rehabilitation
Replacement
Major
Maintenance
Thresholds Minor Maint
Thresholds Major Maint
Thresholds Rehabilitation
Thresholds Reconstruction
Time (years)
for Majors StreetsMinimal Acceptable PQI
Pavement Quality Index (PQI)AC Collectors
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 13
Table 12: Current Minimum Acceptable PQI Values
FUNCTIONAL CLASS MINIMUM ACCEPTABLE PQI
TRIGGER
Alleys
Local Street
Minor Collector
70
Major Collector
Minor Arterial
Major Arterial
75
As streets continue to deteriorate due to inadequate maintenance (funding or neglect), they
often exhibit distresses and other characteristics in which maintenance type activities are no
longer viable options, therefore, they become in need of rehabilitation. The cost for
rehabilitation as opposed to maintenance can be as high as 5 times greater, and as a result,
fewer miles of streets can be serviced for the same amount of available budget dollars.
Once streets fall below a PQI of 30 or 40, they generally need extensive treatments to the
overall pavement structure. Full reconstruction involves the complete removal and
replacement of the pavement surface and selective or full replacement of the street base
and/or sub-base. Often reconstruction can also involve curb, gutter and other drainage
repairs that can be readily attributed to the street deterioration. Reconstruction is extremely
costly (over 10 times the cost of maintenance) and will eat up any available budgets in no
time. In addition the work is often a lengthy and disruptive process and a nuisance in the
eyes of the public.
Table 13 on the following page presents a distribution of the sectional Need Years over a
ten-year programming period for the Fountain Hills street network. The sections with a Need
Year in the first year of the programming period represent the sections that have become in
need of rehabilitation in 2007 as well as those sections which were in need of rehabilitation
before 2007 but which have yet to receive rehabilitation. Therefore, a portion of the sections
in need of rehabilitation in the first year of the programming period represents the prior
backlog. 49 percent of the street network in Fountain Hills is in need of maintenance or
rehabilitation in 2007.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 14
Table 13: Need Year Distribution
The need driven rehabilitation recommendations for the entire street network is provided in
detail by street segment in Appendix A. This text report will include the need year, the
selected rehabilitation alternative as well as the cost of the selected alternative.
HOW MUCH MONEY DO WE NEED?
The amount of funding required can be determined by identifying the optimal rehabilitation
strategy for each pavement section. This process is based on three parameters; 1) the need
year for a section, 2) selecting from a ‘pool’ of feasible rehabilitation strategies and 3)
determining the economic impact of implementing these strategies. The optimal strategy is
determined using life cycle economic analysis techniques, which involve an assessment of
both the effectiveness of each strategy and an estimate of the capital cost to implement the
strategy. It is possible to generate a rehabilitation program based on an economic analysis
for a programming period. This is accomplished by knowing the present condition of each
section in the network, having a comprehensive pavement prediction performance model,
and a set of decision criteria.
To determine how much funding is needed, the Town’s pavement management system
priority programming analysis is utilized and will generate alternative rehabilitation programs
for various budget stream scenarios.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 15
Three (3) separate 10-year budget scenarios have been generated for the years 2007
through 2016, for comparison. They include:
• Scenario 1 - Planned Budget ~ $1.2 Million Annually
• Scenario 2 – Do Nothing
• Scenario 3 – Unconstrained “Need Driven” Budget
Scenario 1 - Planned Budget
The first phase of the rehabilitation analysis introduces an annual or “planned” budget as a
constraint. This Existing Budget scenario uses the approved annual expenditure to generate
a 10-year rehabilitation program. In this case, potential rehabilitation projects must compete
against each other for funding based on cost effectiveness. Table 15 on page 17, identifies
the resulting PQI from implementing the approved budget of $1.2 million per year. With this
approach, the current PQI of 69 would slowly increase to 83 at the end of year 2010 and then
slowly decrease to 78 by the end of 2016.
Scenario 2 - Do Nothing
The do nothing or zero capital expenditure program will demonstrate the network condition
over a ten-year period if no action or remediation is taken to rehabilitate the Town’s streets.
The results of this approach, the current aged PQI of 69 would slowly decrease to 37
towards the end of 2016.
Scenario 3 - Unconstrained “Need Driven” Budget
The Unconstrained Budget scenario is essentially a needs analysis. It assumes that there is
an unlimited amount of funding and labor, equipment and material resources available. As a
result, any pavement section that requires some treatment will be treated with the
appropriate rehabilitation solution in the year that it should be treated, for the greatest long-
term benefit. One of the common results of any Needs Analysis is that it always
recommends large rehabilitation expenditures in the first year of the analysis period. This
occurs because, with unlimited funds, the network Pavement Quality Index (PQI) is more
effectively increased with immediate expenditures, rather than waiting to spend them. This
analysis usually results in significant fluctuation from one year to another.
Table 15(need driven budget), identifies the approximate expenditures that would be
required to meet the annual treatment needs of the Town of Fountain Hill’s pavement
network. This scenario assumes that the correct treatment would be applied in the correct
year, to maximize pavement life. With this approach, the current PQI of 69 would raise to 88
in year one and then slowly decline to 77 at the end of 2016. While a needs analysis
(Unconstrained Budget) is not practical, it does have value. It identifies the true needs of the
system, without bias.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 16
Table 14: Need Driven Pavement Rehabilitation ~ Summary by cost by Strategy /yr
Rehabilitation
Year Slurry Seal Micro
Surfacing
2” Full Mill &
Overlay
Reconstruct 3”
AC / 6” AGB Total
2007 $1,915,705 $716,607 $5,288,220 $945,346 $8,865,878
2008 $133,250 $29,613 $162,863
2009 $166,019 $70,345 $236,364
2010 $312,571 $120,221 $432,792
2011 $507,028 $102,236 $609,264
2012 $579,859 $164,371 $744,230
2013 $658,664 $146,817 $805,481
2014 $316,248 $93,428 $409,676
2015 $160,143 $38,255 $198,398
2016 $123,670 $27,532 $151,202
Total Network $4,873,157 $1,509,424 $5,288,220 $945,346 $12,616,147
Discussion of Results
Each of the above scenarios will yield a different resultant network PQI at the end of the
analysis period. The comparison of the three (3) scenarios can illustrate how adequate the
planned budget for the Town of Fountain Hills’s pavement network is, over the analysis
period. These results of the budget analysis are summarized in the Network Performance
Summary Report presented in Table 15 on the following page.
This report can be a powerful tool in that it allows the user to easily examine the effect of a
specified budget stream on the performance characteristics of the network. Other sensitivity
analyses, such as the effect of variations in rehabilitation unit costs, required pavement
serviceability levels, and rehabilitation policies as reflected by the decision process can now
be easily adjusted on future analysis.
The network average PQI at the end of 10 years is predicted to be 78 for the $1.2 million
existing annual budget. This will leave 21% of the network below the minimum PQI or
remain deficient at the end of the 10 year analysis period.
Current reinvestment needs (backlog), or the amount required to bring the assets to an
acceptable condition, is $8.9 million for pavements. The backlog is also shown in Table 15
on the following page in the first year of analysis (2007) under the “need driven” category.
Note: An inflation factor was used to convert the costs from 2007 to an equivalent unit cost
for the implementation year of the proposed rehabilitation alternative. The inflation rate was
set at 2% per year.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 17
Table 15: Network Performance Summary – (3 Scenarios)
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 18
HOW DO WE ENSURE LONG-TERM AFFORDABILITY?
The accumulated investment of public funds expended to construct and maintain a pavement
network generally amounts to a substantial figure. The Town of Fountain Hills contains 395
lane miles of paved streets. Together, these streets represent approximately 30 million
square feet of pavement. At an average replacement cost of $4.80 per square foot, for the
pavement construction costs, (i.e., 20% for drainage improvements, design, inspection, and
other overhead and administrative costs have been included) this represents an
infrastructure asset value to replace the entire street network in excess of $146 million in
today’s dollars.
Total replacement is not a feasible plan to long-term affordability. In order to implement a
less expensive approach, information concerning the condition of the network, its rate of
deterioration, and the impact of maintenance and rehabilitation efforts on pavement
serviceability levels are required. It is therefore necessary to monitor the performance of
each section of the pavement network on an ongoing basis.
The Town is well on its way to the ongoing monitoring of a comprehensive pavement
management system. We trust this report and associated recommendations will provide the
basis for defining the direction moving forward towards answering the question of ensuring
long-term affordability in pavement management.
RECOMMENDATIONS
1. Planned Annual Budget: In reviewing the results of Table 15, it is evident that a
$1.2 million annual budget for the pavement network is sufficient to maintain the
current average PQI. Based on the “Need Driven” analysis results for the first three
to four years of the analysis period, it appears that the planned annual budget is a
realistic amount to expect in order to be able to maintain the residential street network
at the desirable level of service.
2. Outlook in next 3-4 years: Although Table 15, provides a predicted pavement
network performance outlook for a ten-year period, it should be noted that due to the
after rehabilitation PQI specified in the decision process, it is unrealistic to rely on the
predicted results for a period beyond three or four years. Therefore, it is
recommended that the budget and “needs” trends for the street network should be
derived from the results of the first three or four years of analysis only.
3. Minimal Acceptable Levels of Pavement Performance: Adjustments to the minimal
acceptable levels (triggers) has direct impact on the expected level of service of the
Town’s pavement performance. Setting PQI triggers too high causes annual
rehabilitation budgets to become unaffordable and the system becomes inefficient in
terms of the length of time between overlays (the higher the PQI trigger, the more
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 19
frequent the rehabilitation cycle). Setting the PQI triggers too low results in an
insufficient amount of backlog selected for rehabilitation and the overall performance
of the network will deteriorate with time. PQI triggers that are too low also result in a
larger number of sections being selected for ‘heavier’ rehabilitation. Earlier
intervention, that is a higher PQI trigger, allows ‘lighter’ rehabilitation strategies to be
implemented.
The 10-year PQI target was selected to maintain the entire Town of Fountain Hills
pavement network at its current level of service, which is in the “good” range. A 10-
year backlog of between 10% and 25% is desirable. Above 25%, the backlog may
become unmanageable and below 10%, the Town may be spending more money
than is necessary on street rehabilitation. Since the backlog for the Town is currently
at 49%, it is recommended for a long term effect that the Town continue to be
proactive in their maintenance strategies which allow for ‘lighter’ rehabilitation
strategies to be triggered in the pavement management system.
4. Schedule Regular Condition Updates: It is recommended that the Town continue to
collect pavement condition data so the present status or condition of the streets is
monitored on a regular basis. This is particularly important given the Town’s desire to
maintain the street network condition at reasonable level of service. This will also limit
the reliability of the prediction of future pavement performance and recommended
rehabilitation programs to a three-to-four year analysis period.
5. Annual Update Program: Another way to monitor the pavement network and
maintain the integrity of the data is to update a portion (1/3rd) of the network annually.
With this approach we usually recommend that the network be divided in a
geographic one-third area. As a result, the network is current every three-year cycle
so no section is more than two cycles (years) old. Therefore, the result of the
maintenance & rehabilitation analysis is more accurate when using the most recent
data to determine the program plans from a year-to-year basis. This also creates an
annual budget for the operation and upkeep of the pavement management and keeps
it in the forefront in the minds of the stakeholders so this system is not neglected and
only looked at every three years.
6. Present Status and Needs Analysis: Based on the results outlined in this report the
Town’s street network is currently providing an adequate level of service. However,
the analysis also indicates that there are significant backlog requirements as
illustrated by the 49 percent of the network with a Need Year of 2007.
Given these results, the primary focus for the Town over the next 3-5 years should be
to put a program in place to significantly reduce the backlog. With approximately $8.9
million identified in 2007 alone, it may be impractical from a budgetary perspective to
attack this backlog over the short term. As a result, to further maximize the street
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
FHills Pavement Present Status Report KHv5.doc 20
improvement budget, total reconstruction work should be limited to those street
segments that carry high volumes of traffic or require additional infrastructure renewal
such as water, sewer and other utilities. Coordination between these various
stakeholders is critical.
In addition, despite some of the streets exhibiting poor surface distress and
roughness qualities, there appears to be suitable material to provide adequate
support of the anticipated traffic loads. As a result, local residential streets may not
need to undergo total reconstruction procedures and rehabilitation treatments could
be used as viable options. Rehabilitation of these streets may include such
alternatives as 1) overlays, 2) mill and overlays, and, 3) slurry applications all of which
will help reduce the backlog of work and extend the life of the existing pavements.
Any proposed projects should however incorporate proper investigation of the
pavement structure and other factors such as drainage which are directly related to
the performance of the pavement over time.
In order to protect the capital investment the Town of Fountain Hills has already
made, it is imperative for public works staff to continue a proactive maintenance
approach. The ongoing use of maintenance type strategies such as crack sealing,
surface treatments and thin overlays (Micro-surfaces) will extend the life of those
streets that are predicted to become needs in greater than 3-4 years from now. This
reduces the need for major rehabilitation and reconstruction well into the future.
Streets do wear out over time and will eventually need reconstruction. Keeping a
backlog of street repair manageable only makes sense and is good practice so the
Town does not get caught off guard with a crisis of failing roads.
FUTURE PAVEMENT MANAGEMENT STRATEGY
By beginning the process of educating the community to the need for sustainable
management of the pavement infrastructure, the impacts of resident or user rates can be
significantly reduced, especially if a reserve fund is utilized to mitigate the impact of the
future peaks in investment needs. We hope this section includes the essential tools which
can be used to begin the education/communication process thus providing a systematic
process to assist pavement managers and decision-makers in 1) Selecting cost-effective
strategies and actions to improve efficiency and safety of their pavement network and, 2)
Protecting the investment made in the pavement network.
Ultimately, the goal is to provide the citizens of Fountain Hills with a safe and efficient
transportation network for all users and protect the value and condition of one of the Town’s
most valuable infrastructures for many years to come. We hope the report includes the
essential tools, which can be used to begin the education/communication process and
through our expertise and determination, we look forward to the opportunity in assisting
Town on future projects.
PAVEMENT MANAGEMENT SUMMARY
PRESENT STATUS REPORT
Streets
November 11, 2007
A.
Appendix A~ Pavements ~ Street Listing and Needs Assessment
The Appendix A ~ Pavements ~ Street Listing and Needs Assessment is provided in a
separate pdf document provided with this present status report. This street list document is also
provided in an electronic spreadsheet format and available for linking into the Towns GIS street
centerline file.