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TRB Webinar: Maintenance Practices for Pavement Marking Retroreflectivity
TRB Webinar: Maintenance Practices for
Pavement Marking Retroreflectivity
Today’s Presenters and Moderator Paul Carlson, Texas Transportation Institute at Texas A&M
University, [email protected]
Jill Morena, Michigan Department of Transportation, [email protected]
Lynnette Firman, Michigan Department of Transportation, [email protected]
Charles Holzschuher, Florida Department of Transportation, [email protected]
Chris Howard, North Carolina Department of Transportation, [email protected]
Eric Donnell, Penn State University, [email protected]
Introductory Remarks
Paul CarlsonTexas Transportation Institute at Texas A&M University
Chair of TRB’s Signing and Marking Materials committee
TRB Announcements:
Upcoming Webinars for 2010 will be announced on TRB’s websitehttp://www.trb.org/ElectronicSessions/Public/Webinars1.asp
Follow TRB on Twitter @TRBofNA http://twitter.com/TRBofNAWe’ll be posting transportation topics, TRB news, and, of course, information from our 89th Annual Meeting, January 10 -14, 2010 in Washington, D.C.
Annual Pavement Marking
Program
Jill Morena & Lynnette FirmanMichigan Department of Transportation
MUTCD
2007Sign Retroreflectivity Minimum Criteria
Established
PresentFHWA Working to Propose Minimum
Pavement Marking Retroreflectivity
MDOT
Pavement Marking “Maintenance Program”
Annual Striping
Retroreflectivity Measurements
Snow Plows
Salt
Sand
Why?
Maintenance Program
Approximately 85% of all State Trunklines are Striped Yearly with
Waterborne or Sprayable Thermoplastic
Construction Projects Omitted
Special Markings are Replaced in Maintenance Contracts
Maintenance Program
CostsAverage Unit Price per Foot
4” Waterborne = $0.044” Sprayable Thermoplastic = $0.09
Approximately $16 Million Annually
Retroreflectivity Contracts
Maintenance Long Line Markings areMeasured by Retroreflectivity Contractsfor a Contractor Incentive/Disincentive
Started in Late ’90s
PurposeContractor Responsibility
Ensure Quality LinesDecreased Workforce
Retroreflectivity Contracts
20% of the State Trunklines Striped in the Maintenance Contracts
are Measured for Retroreflectivity
Don’t Measure Construction
Random 2 Mile Segments
Via Contractors
Retroreflectivity ContractsIncentive/Disincentive Payment
2009-2010 Example
Centerlines, Lane Lines and Edge Lines
White Lines Yellow Lines
Ave. Segment Reading (in millicandelas) Adjustment Factor Ave. Segment Reading
(in millicandelas) Adjustment Factor
≥321 +0.15 ≥186 +0.15
240-320 0 140-185 0
175-239 -0.15 125-139 -0.15
101-174 -0.50 101-124 -0.50
≤100 -0.80 ≤100 -0.80
Retroreflectivity Contracts
PROSYears of Information That Says…
A Brighter Line in Fall; A Brighter Line in Spring
(Not a Direct Correlation)
Increased Retroreflectivity Numbers Over the Years
Sprayable Thermoplastic Chart
Waterborne Chart
Retroreflectivity Contracts
CONSDoes Not Give Us Information on
Presence
Decreased “Man in the Field”
Inspection
PastMDOT Program – One MDOT Van
Years of Durable DataContract with University
PresentOne MDOT Van
Long Lines Around the State by RequestDurable or Maintenance Materials
Retroreflectivity of Durables
Retroreflectivity of Special Markings
Handheld RetroreflectometersTwo in State
Very Seldom Used
Spot Locations
For Information Only
Maintenance Program
Confident with Our ProgramWhen and If Minimum Numbers are
Required
Stepping Stone to Future MUTCD
Requirements
Contact Information
Jill Morena, [email protected]
517.373.3340
Lynnette Firman, [email protected]
517.335.2837
Use of Mobile Retroreflectivity For Pavement Marking Maintenance Strategies
December 16, 2009 Charles Holzschuher, P.E.
2
Contribution & Involvement
u Central Office Chester Henson, P.E. – Pavement Design - FDOT
u State Materials Office Bouzid Choubane, Ph.D., P.E. - State Pavement Materials
Engineer – FDOT
u University of North Florida Jim Fletcher, Ph.D., P.E. – Assistant Professor of Mechanical
Engineering
Josh Sevearance – Technical Research Engineer – MRU Operations
u Drivers need for light doubles every 13 years
u Slower response time with age
u 12% of the country’s drivers are over the age of 65
u 17% of Florida’s drivers are over the age of 65
u Fatalities are 3 times more likely at night
Pavement Marking Information
Can you determine any retroreflective
deficiencies?
Night Time Marking Visibility
Climate Conditions
Rain
Fog
SnowUltraviolet light &
heat
Glass Spheres
Dispersion
Embedment depth
ClarityRefractive
Index
Marking Material
Construction
Type
ColorThickness
Other
Roadway debris
Abrasion by traffic
Dirt & sandPavement Texture
Factors that Influence Retroreflectivity
u It is difficult to precisely determine when it is the best time to replace pavement markings
Too late compromises safety,
Too soon increases maintenance cost!
Current Re-Striping Determinations
6
u Visual Inspection
Windshield Survey
Subjective (pass/fail)
u Handheld Retroreflectivity
Site Specific
Requires M.O.T.
u Prescriptive Method
Re-striping cycles
Inefficient
Need for a New Stripe Evaluation Tool
u Efficient means to measuring retroreflectivity
Highway speed testing
No maintenance of traffic required
Continuous data collection
Can be used day or night
u Improve safety for roadway users and field personnel
7
8
FDOT’s Mobile Retroreflectivity Unit (MRU)
30 meters
Observation Angle = 1.05
Co-entrance Angle = 1.241.2 m
0.65 m
Observation Angle = 1.05
10 meters
Co-entrance Angle = 1.24
1/3rd scale of 30 meter geometry (Used in FDOT unit)
Standard 30 meter geometry
0.22 m
0.4 m
9
Theory & Component Overview
10
FDOT’s Current Work
u In Development:
Evaluating the MRU Sensitivities
Pavement Marking Management System (PMMS)
Standard Operational Procedures
Quality Assurance Procedures
11
Pavement Marking Management System (PMMS)
u Centrally Located
u Optimization of maintenance dollars
u Evaluation of construction techniques
u Degradation Rates
u In-house database
u Web based
12
Pavement Marking Management System (PMMS) – Upload Screen
13
Pavement Marking Management System (PMMS) - Categoriesu Retroreflectivity measurements are classified into four
categories
Inventory - Data is collected to monitor current retroreflectivity characteristics of the state highway system
Special Request - Roadway sections requested from research or safety related
Overlay - Roadways that have been resurfaced and permanent striping placed
New Construction - Roadways that have, new, added, or reconstructed lanes with permanent striping in place
14
Pavement Marking Management System (PMMS) - Database
In Need of Restriping
(Retro < 150)
Near End of Useful Life
(Retro 150- 250)
Press Here
15
Pavement Marking Management System (PMMS) – Video Imaging
16
Pavement Marking Management System (PMMS) – Geographical Information
17
Pavement Marking Management System (PMMS) – Excel Viewer
18
Detailed Operational Proceduresu An operations manual is being developed that contains
Field Test Protocol
Data Processing
Calibration
Maintenance
Trouble Shooting
19
Quality Assurance
u A Quality Assurance procedure is being developed to ensure:
The equipment and operators can adequately meet the performance requirements such as:- Equipment sensitivity- Calibration procedures- Software- Known Retro Values- Field Verification
20
Quality Assurance – Calibration Facility
u Facility Development
MRU Light Tunnel
Uniform Conditions
Research Experiments
u Evaluate
Stationary Creep
Lateral Wander
Field Reference Sections
Quality Assurance – Stationary Creepu Stationary Creep: Demonstrate the MRU can maintain a consistent
reading over a four hour period in a laboratory setting.
18
18.5
19
19.5
20
20.5
21
150151152153154155156157158159160161162163164165
12:5
3 PM
1:09
PM
1:25
PM
1:40
PM
1:56
PM
2:12
PM
2:28
PM
2:43
PM
2:59
PM
3:15
PM
3:31
PM
3:47
PM
4:02
PM
4:18
PM
4:34
PM
4:50
PM
5:06
PM
Cha
nge
in T
empe
ratu
re (
C)
Cha
nge
in R
efle
ctan
ce (m
c/m
2 /lux
)
Time
Stationary Creep RL Tempurature
20 min warm up period
Quality Assurance – Lateral Wanderu Lateral Wander: The standard will be moved laterally across the
effective scan width of the retroreflectometer unit and retroreflectance values recorded.
0
50
100
150
200
250
-25 -20 -15 -10 -5 0 5 10 15 20 25
Ref
lect
ance
(mcd
/m2 /l
ux)
Position from Centerline (in)
Lateral Wander
Max Scan Width
6" Ceramic Block
Bad Alignment
Good Alignment
Future Developments Needed
u Develop standardized test procedures for mobile retroreflectivity (AASHTO, ASTM)
Precision (Repeatablity/Reproducibility)
Accuracy (Bias)
u Common Reference Standard
Ceramic Block
Robust pavement striping
24
Questions/Comments
North Carolina’s Pavement Markings Performance System
Roadway System
Over 80,000 Road miles
The 5400 miles of our existing and proposed Strategic Highway Corridors make up only 7% of the State’s Highway System, but carry approximately 45% of the traffic.
NC is the largest state maintained highway network in the US (Wikipedia)
Focus Resources Based on Three Tier System
Statewide Tier - Interstates and major primary highways which serve long-distance trips, connect major population centers and primarily provide a mobility function.
Regional Tier - Minor US and NC designated highways which typically serve high levels of demand for short distances, e.g.., commuter travel.
Subregional Tier - Minor NC routes and secondary roads which serve localized, short distance movements, low demand and provide land access to homes and businesses.
Marking Materials and Previously Estimated Service Life Over the Past 30 years
Materials Estimated Service Life
(yrs)Paint- Switched to water based in 96. Use on all roads with less than an AADT of 4000 vehicles/day 1.5 to 2Thermoplastic- 1974 symbols and 1981 long line switched to Alkyd/Maleic in 92 4 to 6Methyl Methacrylate- Evaluated in the early 90s N/A Polyurea- Started in the early 90s. Use on all concrete roadways and on some asphalt roadways where there will be snowplowing 4 to 5Epoxy- Started in early 80s. Moratorium from 84 to 88 2 to 3
Cold Applied Plastic (Tapes)- Use on concrete bridge decks where thermo will be used on the rest of the roadway 4 to 6Heated In Place Thermoplastic- Mainly for state maintenance forces 5 to 7
Profiled Markings- Areas in the eastern part of the state 5 to 7Sprayed Thermoplastic – Have used N/A
Collecting the Data
Over 30,000 lane miles of roadway (~12%) between 2001 and 2007These readings are used for inspection and life cycle analysisScanned until the markings were replaced or determined
retro was to low.
Mobile Readings Hand held Readings
Evaluating the Data Wanted a data driven, performance based approachMaximize cost savings Increase service life Justify types of markingsAsset management data collection for supporting decision
Processes
Federal standards for Retroreflectivity (RL)
NCSU studied the dataUsed 2 year contract to tell us what we had and create
degradation models
Category Model R2
Consolidated RL = 190 + 0.39*RL Initial – 2.09*time – .0011*AADT + 20.7*X1 – 20.7*X2 + 19*X3 – 19*X4 .60
White Edge RL = 223 + 0.39*RL Initial – 2.09*time – 0.0010*AADT .38White Middle RL = 173 + 0.59*RL Initial – 2.89*time – 0.0026*AADT .53Yellow Edge RL = 193 + 0.40*RL Initial – 1.69*time – 0.0016*AADT .45
Yellow MiddleRL = 128 + 0.41*RL Initial – 1.99*time
.64
PaintRL = 55.2 + 0.77*RL Initial – 4.17*time
.75
Degradation Model
X1=1 if edge line, 0 otherwise X2=1 if center line, 0 otherwiseX3=1 if white line, 0 otherwise X4=1 if yellow line, 0 otherwise
LOS Thermoplastics Waterborne Paint White Yellow White Yellow
Blue (A) ≥ 275 ≥ 210Green (B) 200-274 145-209 ≥ 250 ≥ 215Yellow (C) 175-199 125-144 150-250 115-215Amber (D) 150 -
174100 - 124 100-149 65-114
Red (F) ≤ 149 ≤ 99 ≤ 99 ≤ 65
All values are in mcd/m2/lx
NCDOT established statewide standards based on proposed Federal Standards
Performance-based Service LifeCategory Minimum
Standard (mcd/lx/m2)
Initial Spec Value
(mcd/lx/m2)
Installed Thickness
(mils)
Estimated Service Life
(months)
Estimated Service Life
(years) White Edge Thermoplastic
150 375 90 100 8.3
White Middle Thermoplastic
150 375 120 76 6.3
Yellow Edge Thermoplastic
100 250 90 105 8.75
Yellow Middle Thermoplastic
100 250 90 65 5.4
White Paint 100 220 15 31 2.6
Yellow Paint 65 200 15 26 2.2
Using an AADT of 10,000 vehicles/day
Immediate Conclusions• Why are we using paint?• Should be a durable pavement
marking State• Mitigate exposure of State
workers and contractors to traffic, and user delays (Once every 8 years is better than every 1 or 2 years)
Polyurea- 5 good years on interstates
Epoxy- 2 to 4 years
12 monthPolyurea
12 monthEpoxy Paint
Develop Strategies
Department data communicates with one common data system
The Date of when the markings are placed
Begin and end points (Location referencing)
Initial RL value
Upload degradation models in the Department’s Maintenance Management System (MMS)
Associate timeline of pavement marking degradation in a holistic asset management system
Asset Management
Develop Goals and Policies
Assess, develop and maintain an asset inventory
Perform a condition assessment and conduct performance modeling
Predict when future markings should be replaced using degradation models
Incorporate pavement marking in a Holistic Asset Management System
What Now?• Now we have this data, where do we stop?• Read 10% annually?• Audit initial installation (in-house & contract)
• Need more polyurea, paint and epoxy data in the western part of the State
• Training (Pavement Marking Rodeo)
Ongoing Cooperative Research NCSU
– Finished a two-year marking research project– Continue to measure 25 roads with paint markings
for 2.5 years ( measured every 6 months starting from November 2007)
– Air Force Institute of Technology– Impact of snow removal on thermoplastics/paints– Performance modeling of polyurea markings– Combining MMS and marking data into an asset
management system
Still need initial inspection
Chris Howard Signing and Delineation Standards [email protected]
Questions?
The Thomas D. LarsonPennsylvania Transportation Institute
Use of Pavement Marking Degradation Models to Manage Pavement Marking Systems in
Pennsylvania
TRB Webinar: Maintenance Practices for Pavement Marking Retroreflectivity
December 16, 2009
Presented by: Eric Donnell, Ph.D., P.E.
Acknowledgements
• Co-authors– Lekshmi Sasidharan, Ph.D. Candidate (CE)– Vishesh Karwa, Ph.D. Candidate (Statistics)
• Sponsorship– Bureau of Highway Safety and Traffic Engineering
• Kenneth Williams and Matthew Briggs– Research Division
• Lisa Karavage
Overview• Purpose and Motivation• Background• Empirical Setting• Analysis Methodology• Analysis Results• Conclusions
Purpose• Pavement markings are important highway
infrastructure asset• Annual expenditures for pavement markings
on state-maintained highways is ~ $911 million in U.S.
• Retroreflectivity is measure of nighttime visibility and degrades over time
• Need to replace pavement markings when reaching end of useful service life
Motivation• PennDOT maintains ~ 40,000 lane-miles of
roadway– Most contain waterborne paints– Using some epoxy pavement markings
• Current re-striping practices:– Waterborne paints: every year– Epoxy: every two years
• Need quantifiable service life estimates to cost-effectively re-stripe pavement markings
Background• Marking type and color, pavement surface, age,
traffic passages, environmental, and application practices influence service life
• Service life estimates for similar markings vary widely in past research due to:– Variable minimum retroreflectivity thresholds– Data (longitudinal vs. transverse markings; type of
retroreflectometer; sampling plan)– Geography– Application methods– Statistical analysis methods
Example Service Life EstimatesRoadway Typea Material
Number of Pavement Markings
in Sample
Service Life Estimate (months)
Average Range
Freeway
White Epoxy 11 12.8 3.4 – 34.0Yellow Epoxy 7 23.2 12.6 – 47.5
White Waterborne Paint 3 10.4 4.1 – 18.4
Yellow Waterborne Paint N/A N/A N/A
Non-freeway(Posted speed < 40 mph)
White Epoxy 2 39.4 29.2 – 49.7Yellow Epoxy 2 43.9 34.7 – 53.1
White Waterborne Paint N/A N/A N/A
Yellow Waterborne Paint N/A N/A N/A
Non-freeway(Posted speed > 45 mph)
White Epoxy 5 38.8 26.1 – 56.0Yellow Epoxy 6 44.1 35.8 – 57.8
White Waterborne Paint N/A N/A N/A
Yellow Waterborne Paint N/A N/A N/A
a Service life estimates are for roadways without retroreflective raised pavement markers or fixed roadway illumination.
Source: Migletz et al. (2001)
Empirical Setting• Random sample of roadway segments across
state:– Each segment ~ 0.5 miles long– 51 segments with waterborne paint
• 128 different pavement markings (edge lines, centerlines, broken lines)
– 37 segments with epoxy• 105 different pavement markings
• All segments on roads classified as arterials (including Interstates)
Waterborne Paint Specifications• Wet-film thickness:
– 15 mils + 1 mil for yellow markings and lane lines– 12 mils + 1 mil for white edge line markings
• Glass beads:– PennDOT Type A at rate of 7 lbs/gallon of paint.
• Minimum retroreflectivity (after 21 days):– 250 mcd/m2/lux for white markings– 165 mcd/m2/lux for yellow markings
Epoxy Specifications• Wet-film thickness:
– 20 mils + 1 mil for all types• Glass beads:
– Double-drop method at rate of 10 lbs/gallon of PennDOT Type A glass beads and 10 lbs/gallon of PennDOT Type B glass beads
• Minimum retroreflectivity (after 21 days):– 250 mcd/m2/lux for white markings– 200 mcd/m2/lux for yellow markings
Data Collection• Retroreflectivity collected using mobile
retroreflectometer by contractor.– 500 measurements/marking type/road segment– Contractor entered average measurement into
analysis database– Measurements recorded in direction of traffic flow
• Five measurements recorded on each pavement marking between May 2007 and May 2008
• Installation date of markings known
Other Data Elements• Average annual daily traffic (AADT)• Pavement surface type (PCC or ACC)• Linear reference (route, county, segment)• Snow zone regions developed by PennDOT
based on 20 years of historical data:– 0-40 inches– 40-60 inches– 60-100 inches
Analysis Methodology• Statistical Approach
– Panel data models– Consider minimum threshold value of 75 and 100
mcd/m2/lux
itiitit X νµβ ++=Retro
• Life Cycle Cost Analysis– Net present value– Compare current re-stripe practice to re-striping
practice based on service life estimates
Analysis Taxonomy
Analysis Protocol
Data SummaryCategorical Variables
Variable Name Categories Proportion of Sample in Category Waterborne
paint Epoxy
Pavement marking type
White Edgeline 38.9 36.8 White Skip Line 21.2 26.6 Yellow Line 39.9 36.6
Pavement surface type
Concrete 28.7 26.8 Asphalt 71.3 73.2
Maintenance functional class
MFC A 34.7 40.8 MFC B 29.6 45.2 MFC C 35.6 14
Snow zones
0-40 inches annually
44.2 25.2
40-60 inches annually
36.1 58.2
60-100 inches annually
19.7 16.6
Number of observations 579 424 Continuous Variables
Variable Name Pavement marking material
Mean Standard Deviation
Min Max
Retroreflectivity (mcd/m2/lux)
Waterborne 170.93 74.93 34 381 Epoxy 172.54 77.8 53 568
Average daily traffic (veh/day)
Waterborne 12,061 10,318 900 57,900 Epoxy 4679 6218 285 40,939
Age of pavement marking (days)
Waterborne 180.62 129.05 1 600
Epoxy 458.66 371.277 3 1434
Sample Data(Waterborne Paints)
010
020
030
040
0R
etro
refle
ctiv
ity (m
cd/m
^2/lu
x)
0 200 400 600Time (Days)
g g
5010
015
020
025
0R
etro
refle
ctiv
ity (m
cd/m
^2/lu
x)
0 200 400 600Time (Days)
g
White Edge lines Yellow Edge lines
Analysis Results (Epoxy)
0
50
100
150
200
250
300
50 150 250 350 450 550 650 750 850 950 1050 1150 1250
Ret
rore
flect
ivity
(mcd
/m2 /l
ux)
Time (Days)
White Edge LinesYellow Edge Lines
Service Life Estimates (Epoxy)
Threshold RL = 100 mcd/m2/lux(service life in days)
Threshold RL = 75 mcd/m2/lux(service life in days)
White Edgeline
White Skip Line
Yellow Edgeline
WhiteEdgeline
White Skip Line
Yellow Edgeline
973 973 773 1253 1253 1052
Analysis Results(Waterborne Paints)
0
50
100
150
200
250
300
50 100 150 200 250 300 350 400 450 500 550
Ret
rore
flect
ivity
(mcd
/m2 /l
ux)
Time (Days)
Dir ADT =12000 Dir ADT=2000 Dir ADT=22000
White Pavement Markings
Analysis Results(Waterborne Paints)
Yellow Pavement Markings
0
50
100
150
200
50 100 150 200 250 300 350 400 450
Ret
rore
flec
tivity
(mcd
/m2 /
lux)
Time (Days)
Asphalt -Dir ADT=12000
Concrete-Dir ADT=12000
Service Life Estimates(Waterborne Paints)
ADTa
(veh/day)
Threshold RL = 100 mcd/m2/lux Threshold RL = 75 mcd/m2/lux
White
Edgeline
White
Skip
Line
Yellow
EdgelinebWhite
Edgeline
White
Skip Line
Yellow
Edgelineb
1,000 467 465 376 538 536 476
5,000 459 449 361 531 521 461
10,000 449 430 342 521 501 442
20,000 430 391 305 501 462 405
30,000 411 353 268 482 424 368
50,000 372 258 194 443 347 294a The retroreflectivity thresholds for ADT are based on the estimated average daily trafficpasses by vehicles in travel lanes adjacent to the pavement marking type indicated. Forexample, the threshold for a white edgeline and yellow edgeline is computed based on one-half of the directional ADT, or one-quarter of the ADT in both directions. The threshold for awhite skip line is computed based on the directional ADT. As a result, the service lifeestimates for white skip lines are lower than that for white edge lines due to increased trafficexposure.b The yellow edgeline pavement marking service life estimates are based on an asphaltpavement surface. To compute the service life for yellow edge lines on concrete pavementsurfaces, add 85 days to the estimates shown .
Life Cycle Costs
Roadway Type
Centerline Miles
Current practice
Based on Estimated Service Life ($)
Waterborne Paints Epoxy
100 mcd/m2/lux
75 mcd/m2/lux
100 mcd/m2/lux
75 mcd/m2/lux
2 lane 9,822 122,488,141 122,488,141 85,791,022 396,581,018 294,265,529
4 lane 3,779 53,018,023 53,018,023 20,629,981 168,257,934 125,626,695
Total 13,601 175,506,164 175,506,164 106,421,003 564,838,952 419,892,224
Savings 69,085,161 144,946,728
Conclusions• Degradation rate of white and yellow epoxy
markings not different• White epoxy markings have higher initial
retroreflectivity than yellow epoxy markings• Traffic exposure, weather not statistically
significant in epoxy pavement marking model• Service life estimates for epoxy:
– 2.7 – 3.4 years for white, depending on threshold– 2.1 – 2.9 years for yellow, depending on threshold
Conclusions (con’t)• White waterborne paints degrade more rapidly than
yellow waterborne paints.• Higher initial levels of retroreflectivity for white
waterborne paints compared to yellow.• Traffic exposure statistically significant in waterborne
paint statistical models, but weather effects were not significant.
• PCC surfaces provided higher levels of retroreflectivity than ACC surfaces when applying yellow waterborne paints.
• Service life estimates for waterborne paints:– 0.7 – 1.5 years based on AADT, type, & threshold for white – 0.5 – 1.3 years based on AADT and threshold for yellow
Implementation• Epoxy markings not cost-effective when compared to
waterborne paints over 10-year life-cycle• Consider 2.5 year re-stripe period for white, and 2.0
year re-stripe period for yellow epoxy based on 100 mcd/m2/lux threshold – Add one year to epoxy re-stripe periods if threshold is 75
mcd/m2/lux• Retain one year re-stripe interval for waterborne
paints based on 100 mcd/m2/lux threshold– Add 0.5 year to re-stripe period for waterborne paints based
on 75 mcd/m2/lux threshold– May need to re-stripe high-volume roads (> 30,000 veh/day)
more frequently
Thank You!Eric T. Donnell, Ph.D., P.E.Assistant ProfessorDept. of Civil & Environmental Engineering212 Sackett BuildingUniversity Park, PA 16802Phone: (814) 863-7053E-mail: [email protected]
