AASHTO Crack Protocol

Brian Michalk, Texas DOTRPUG 2006

Des Moines, Iowa

Overview• TxDOT data collection infrastructure• Overview of crackpanel• Overview of crack steering committee• Overview of system

– Show web interface– Discuss infrastructure, uploads, data requests– amount of data and management– Discuss hardware

• Industry needs– Standardized and extensible reporting protocols– Online data format verification

• Overview of pmis ratings• Opinions on aashto crack

– Does not necessarily correlate– Does it look reasonable?– Differences with txdot

Night Images

Gamma Light Bar Wing

Timeline to now

Planned Timeline

Infrastructure

• New Gadgets– Automated data transfer/PMIS import– Immediate access to uploaded data– Hourly statewide collection status map– Image Browser– Uploaded data status

• Industry needs– Unified reporting protocols– Web based tools to verify data formats

District Network Access Points

Map Status

Image Browser

Same Location from Google

Data Report

TxDOT share (\\despav\VehicleDaily\)

Crack Panel, June 2002

• Various pavements• 247 images with varying levels of distress.• Five people, one second per image• One person rated longitudinal cracked

images four times over several days.• The automated system ran five times in

variable conditions

Repeatability of Longitudinal Visual Rating

Agreement (%)

Freq

uenc

y

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0.2

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0 25 50 75 100

100 images of a pavement were rated 4 times by the same person.

Average agreement= 83%

Person-Person Agreement

p1 p2 p3 p4 p50.80 0.68 0.79 0.71

0.80 0.72 0.74 0.710.68 0.72 0.75 0.770.79 0.74 0.75 0.75

p1p2p3p4p5 0.71 0.71 0.77 0.75

Longitudinal Crack Counts

* 247 images of pavements were rated.

Average agreement=74%.

% Longitudinal Cracks

y = 0.97x + 2.45R2 = 0.999

0.0

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0.0 50.0 100.0 150.0 200.0

1st Scan

2ndSc

an

Crack CountsCounts for 247 images of pavements.

CPU P1 P2 P3 P4 P5Tran

Alli0

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150

TranLongAlli

Brian K. Michalk: Notice that the computer gives answers within the range of the human panel.Brian K. Michalk: Notice that the computer gives answers within the range of the human panel.

Crack CountsPanel is the average of 5 people’s counts.

Long TranAlli

CPUPanel0

50

100

150

CPUPanel

Comparison on Repeatability

* Computer’s repeatability is based on C.V. data; People’s repeatability is based on agreements.

longitudinaltransverse alligator1 person, 4x 83 N/A N/A5 people, 1x 74 83 61

1 computer, 5x 90.2 92.5 90.4

m1

Slide 21

m1 3431 miles of flex127 miles of rigid michalk, 3/17/2006

Fiscal Year 2006 ACP Transverse Cracking

0.00%

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Rating / Measurement

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ive

Perc

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(Lan

e M

iles)

Visual Ratings Automated Measurements

Fiscal Year 2006 ACP Alligator Cracking

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Rating / Measurement

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ive

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e M

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Visual Ratings Automated Measurements

Flexible AASHTO %cracked

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1 11 21 31 41 51 61 71 81 91Rating AASHTO percent lane cracked

perc

ent l

ane

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s

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pct_crk_bwppct_crk_lwppct_crk_owppct_crk_rwpPMIS alligator percentcum pct_crk_bwpcum pct_crk_lwpcum pct_crk_owpcum pct_crk_rwp

Low Standard Deviation

High Standard Deviation

AASHTO % vs Average

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AASHTO percent area

AASH

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rack

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lwp_Avg

Transverse vs LWP average

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0 20 40 60 80 100 120 140PMIS number transverse

AA

SHTO

ave

rage

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cks

LWP

lwp_Avg

Transverse Sealed vs Outside Wheelpath

y = 0.4244xR2 = -0.3134

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PMIS number sealed cracks

AA

SHTO

ave

rage

cra

cks

owp

owp_AvgLinear (owp_Avg)

AASHTO Crack Observations• Need to pay attention to averages per unit area

to compare state to state• When reporting must qualify

– Area of image– Apparent system resolution

• AASHTO– 1mm minimum width– 25mm minimum length

• Not reporting severity• Should separate “outside of wheelpath” into left

and right.