Managing a Statewide Network An overview of the CDOT Pavement Management Program Eric Chavez...

Managing a Statewide Network

An overview of the CDOT Pavement Management Program

Eric Chavez 303.398.6565

Stephen Henry 303.398.6579

Pavement Management Inputs/Processing/Outputs

Pavement Management Models

Regional Project Inventories

DTD data (Traffic and Climate Zones)

Roadway Condition Data

Index Equations

Remaining Service Life

Roadway Images and Inventory

Good/Fair/Poor Maps (Current Network Condition)Future 20-Year Network Condition Projections

Project Costs and Benefits

Project Recommendation Lists

Resurfacing Funding Allocations

Maintenance Project Info

CDOT Chief Engineer’s Objectives (Matching Projects)


Maintained and owned by the Regions.

Historical catalogue of all recorded projects on every highway– Year of construction.– Thickness of asphalt or concrete.– Maintenance history.

Division of Transportation Development (DTD) Data

Traffic loading (20-year ESALs.) Climate zones. Highway limits.


Collected annually. Over 11,000-miles of Colorado

highways. Digital Images of highways,

shoulders, and pavement. Surface distress and severity

collected from the digital images in accordance with the Distress Identification Manual for the Long-Term Pavement Performance Program.

Data reported on 1/10-mile intervals

Condition Data

Distress Types:– Fatigue cracking– Longitudinal

cracking– Transverse

cracking– Corner breaks– Ride quality as IRI– Rutting

Cracking Distress Severities:– Low– Moderate– High

Roadway ImagesCorner break

Fatigue cracking

Index Equations

Transforms raw distress values into a standardized scale.Scale: 0 – 100.100 is a flawless pavement, no distresses.Value of 50 is an RSL of 0.

One index for each distress.

=100-

(

.

Distress LOW

+

Distress MOD

+

Distress HIGH

)

.

100

MAX LOW MAX MOD MAX HIGH

Maintenance Work

Maintenance activities are reported into the system.

The Pavement Management Program is currently investigating more efficient ways to account for preventive maintenance efforts.






Index Equations









Remaining Service Life (RSL) Definition

The estimated number of years, from a specified date in

time, until a pavement section reaches the threshold

distress index. RSL is a function of the distress level and

rate of deterioration. (Pavement Management Manual)

RSL = 0 : The point where a pavement’s condition has

reached a remaining service life of zero years due to

distresses and age. The Remaining Service Life pertains to

the last treatment and not necessarily the entire pavement.

A project level investigation of the pavement is necessary

to determine the best, most cost-effective treatment.

(Pavement Management Manual)

RSL: Site-Specific Regression Curve

0 5 10 15 20 25 30

0

10

20

30

40

50

60

70

80

90

100

Transverse Regression Curve:HWY 2A, D1, MP 3.0 - 4.2Year of Last Work: 2002

Index Values

Project Age

Tra

ns

ve

rse

Ind

ex

Va

lue

RSL

17 – 8 = 9

Threshold Index = 50

(RSL = 0)

Threshold Age

Current Age

Requirements• 5 years worth of data.• St Dev. <10• R2 >= 0.5

RSL: Family Regression Curve

0 5 10 15 20 25 30 35 400

10

20

30

40

50

60

70

80

90

100

Transverse Regression Curve:HWY 24A, D2, MP 212.9 - 218.0

Year of Last Work: 2000

Pavement Group:Asphalt, Medium Traffic, Cool Climate, Depth 4-6"

Indices

Project IdxValue

Threshold (Idx = 50)

Project Age

Tra

ns

ve

rse

Ind

ex

RSL

27 – 21 = 6

Threshold Age

Current Age

Requirements Site• 5 years worth of data.• St Dev. <10• R2 >= 0.5

RSL: Expert Opinion Curve

0 5 10 15 20 25 300

10

20

30

40

50

60

70

80

90

100

Transverse Default Curve:HWY 3A, D1, MP 0.0 - 2.4Year of Last Work: 2009

Pavement Group:Asphalt, Medium Traffic, Cool Climate, Depth <4"

Family Indices

Threshold (Idx = 50)

Project Age

Tra

ns

ve

rse

Ind

ex

RSL

13 – 2 = 11

Threshold Age

Current Age

Requirements• 5 years worth of data.• St Dev. <10• R2 >= 0.5• Engineering Experience

RSL: Why?

RSLs are a way to take detailed data and generalize it for network level pavement management.

RSLs quantify the life expectancy of a given project, which is valuable information that can be used for practical purposes.

RSL: Scope of Calculation

11,000 miles of data collected.– Approximately 3,700 projects (0.5-5.0

Miles in length) Each Project has five distresses.

– Each distress on each project needs a performance curve

200 distinct pavement families– Each pavement family needs a

regression curve for each of the five distresses

RSL & Maintenance

RSL are augmented by one or two years depending upon the type and timeframe of recent maintenance activities.

The Pavement Management Program is currently investigating more efficient ways to account for preventive maintenance efforts.






Index Equations









Project Costs and BenefitsTreatments: Preventive Maintenance

Preventive Maintenance is a category of treatment that includes any thing from crack seals to chip seals to thin overlays (< 2 inches)

Cost: $6.50/yd2

Trigger:– RSL >= 6– AND all distress index values >= 81

Benefit: Ranges from 1 year to 5, based upon traffic

Treatments: Minor Rehabilitation

Minor Rehabilitation includes most treatments that range 2 – 4 inches in depth.

Cost: $30.00/yd2

Trigger:– RSL 2 - 6– AND at least one distress index values

between 61-80 Benefit: Ranges from 7 year to 12,

based upon traffic

Treatments: Major Rehabilitation

Major Rehabilitation includes most treatments greater than 4 inches.

Cost: $41.00/yd2

Trigger:– RSL <= 5– AND at least one distress index values

between 45 - 70 Benefit: Ranges from 13 year to 20,

based upon traffic

Treatments: Reconstruction

Reconstruction is a treatment that replaces the entire surface and supporting structure of a highway.

Cost: $166.50/yd2

Trigger:– RSL = 0– AND at least one distress index <= 50

Benefit: 25 years






Index Equations









Good/Fair/Poor Ratings

Good/Fair/Poor (G/F/P) - The G/F/P designation is a categorization of a pavement’s RSL. A Good pavement section has an RSL greater than or equal to 11 years. A Fair pavement section has an RSL equal to 6 and less than or equal to 10 years. A Poor project has an RSL of 5 years or less. ●Good: RSL >= 11●Fair: RSL >=6 and <=10●Poor: RSL <= 5

G/F/P Map: CDOT Network

G/F/P: CDOT Network

2011 Condition Distribution

●Good: 28% (3,067 miles)

●Fair: 20% (2,167 miles)

●Poor: 18% (2,062 miles)

●Poor-0: 34% (3,691 miles)

20-Year Condition Projection

20112012

20132014

20152016

20172018

20192020

20212022

20232024

20252026

20272028

20292030

20310%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100% 2011 20-Year Good/Fair Projections

~$480 M/YR

~$400 M/YR

~$315 M/YR

2035 Re-source Al-location, ~$274 M/YR

Historical STP In-vestment, ~$197 M/YR

Years

% G

oo

d /

Fai

r C

on

dit

ion

s

Average Annual Budget

Vision

Goal


Regional Funding Allocation Equation

5P= the sum of the previous five years of

resurfacing funds for a given Region.

10F = the sum of the predicted ten years of

resurfacing funds for a given Region, as optimized

by the Pavement Management models.

2 X 5P + 10F 20

Resurfacing Funding Allocation

Regional Funding Allocation - Continued

90% of Regional funding is based upon the equation.

10% of Regional funding is allocated based upon miles of RSL=0 roads in the Region.

Project Recommendation

The Pavement Management Program selects the treatment with the greatest benefit at the lowest cost. That treatment is applied at the best possible time in the life of the project.

Traffic is a weighted factor in the benefit that tips the cost-benefit ratio in favor of higher-traveled highways.

Chief Engineer’s Objectives

Regions run their Region-Specific models and generate a list of the most cost effective projects in their Region. This list is used to create the Regions’ 3-year resurfacing plan.

Chief Engineer Objective: 70% of planned resurfacing projects match Pavement Management Recommendations.– Currently achieving 76% match.






Index Equations









Managing a Statewide Network An overview of the CDOT Pavement Management Program Eric Chavez...

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