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Pavement Health Track Graphical User Interface, User's Manual 2.x

Technical Information

The PHT analysis engine quantifies the RSL of the pavement for each highway section using the simplified MEPDG-based pavement performance prediction models. The PHT analysis engine receives highway data and parameter metrics and determines the pavement RSL in accordance with its implementation process presented in Figure 52.

A word chart shows the sequence of inputs and processes that lead to RSL forecasts. At the top, various types of data feed into Raw Data, with flow downward to Process Raw Data, and further downward to Compute Critical Pavement Responses. These outputs flow downward into a set of three analysis routines: NEW HMA and HMA/HMA, New Rigid (JPCP), and Composite HMA/PCC. The flow merges downward into the Outputs, with Tables for Project Level Outputs and Adjusted Predicted Performance/Condition as well as for RSL.
Figure 52. RSL Forecasting Process

PHT Data Schema

Table 5. PHT Data Fields
Field Name Type Description
ID integer Unique record identifier.
year_record integer Year of record.
state_code integer State FIPS code.
route_id text Route identifier.
begin_point single Beginning milepost.
end_point single Ending milepost.
section_id text State wide unique section identifier, 32 characters max.
section_length single Overall section length.
f_system integer The FHWA approved functional system classification.
urban_code integer Urbanized area code
facility_type integer Operational characteristics of the roadway.
structure_type integer Section is completely on a structure, tunnel, or causeway.
through_lanes integer Number of lanes of the entire facility.
speed_limit integer Posted speed limit.
aadt integer Annual average daily traffic.
aadt_single_unit integer AADT for single unit trucks.
aadt_combination integer AADT for combination trucks.
future_aadt integer Forecasted AADT.
future_aadt_year integer Year of forecasted AADT.
lane_width Single Measure of existing lane width.
shoulder_type integer Type of existing shoulder.
iri integer International roughness index.
psr single Present serviceability rating.
surface_type integer Surface type of the facility.
rutting single Estimate of average rutting.
faulting single Estimate of average vertical displacement between adjacent slabs.
cracking_percent single Estimate of total area with fatigue cracking or percent of cracked slabs.
cracking_length single Estimate of total feet/mile of cracking length.
year_last_improv integer Year in which the roadway surface was last improved.
year_last_construction integer Year the facility was last reconstructed.
last_overlay_thickness single Thickness of the most recent pavement overlay.
thickness_rigid single Thickness of the rigid pavement.
thickness_flexible single Thickness of the flexible pavement.
base_type integer The base pavement type.
base_thickness single Thickness of the base pavement.
climate_zone integer Climate zone for the facility.
soil_type integer Soil class type.
county_code integer County FIPS code.
volume_group integer The AADT volume group for the facility.
expansion_factor single Factor to expand sample data to represent the universe data.

The schema for the PHT result data fields shown in Table 6 are appended to the end of the original PHT source data schema when the PHT analysis is performed.

Table 6. PHT Result Fields
Field Name Type Description
n_RU_Code integer Auto-generated code used by the PHT analysis.
f_RSL_Final_IRI single Predicted IRI at the end of the overall service life.
f_RSL_Final_Rutting single Predicted Rutting at the end overall service life.
f_RSL_Final_Cracking_Percent single Predicted Percent Cracking at the end of the overall service life.
f_RSL_Final_Cracking_Length single Predicted Cracking Length at the end of the overall service life.
f_RSL_Final_Faulting single Predicted Faulting at the end of the overall service life.
f_RSL_Term_IRI_Years single Number of years until the terminal IRI is reached.
f_RSL_Term_IRI_ESALs single Remaining ESALs until the terminal IRI is reached.
f_RSL_Term_Rutting_Years single Number of years until the terminal Rutting is reached.
f_RSL_Term_Rutting_ESALs single Remaining ESALs until the terminal Rutting is reached.
f_RSL_Term_Cracking_Percent_Years single Number of years until the terminal Percent Cracking is reached.
f_RSL_Term_Cracking_Percent_ESALs single Remaining ESALs until the terminal Percent Cracking is reached.
f_RSL_Term_Cracking_Length_Years single Number of years until the terminal Cracking Length is reached.
f_RSL_Term_Cracking_Length_ESALs single Remaining ESALs until the terminal Cracking Length is reached.
f_RSL_Term_Faulting_Years single Number of years until the terminal Faulting is reached.
f_RSL_Term_Faulting_ESALs single Remaining ESALs until the terminal Faulting is reached.
f_Overall_RSL_Years single Overall number of years remaining in the service life.
f_Overall_RSL_ESALs single Overall number of ESALs remaining in the service life.
f_Reliability_RSL single Calculated Reliability RSL.
n_Analysis_Result_Code integer Code (1) indicating the record was successfully analyzed.
f_UDF1 single User defined data field.
f_UDF2 single User defined data field.
f_UDF3 single User defined data field.
f_UDF4 single User defined data field.
f_UDF5 single User defined data field.
f_UDF6 single User defined data field.

Maintenance Mode

The schema for the Maintenance model result data fields shown in Table 7 are appended to the end of the PHT result data schema when the maintenance model analysis is performed.

Table 7. Maintenance Model Fields
Field Name Type Description
f_Treatment integer Code indicating the type of feasible maintenance treatment.
f_SLE single Estimated service life extension.
f_Cost integer Estimated cost of the maintenance treatment.
f_Benefit single Estimated monetary benefit.
f_BCR single Benefit/Cost ratio
f_Reset_IRI single Revised post-maintenance IRI value
f_Reset_Rutting single Revised post-maintenance Rutting value
f_Reset_Cracking_Percent single Revised post-maintenance Cracking Percent value
f_Reset_Cracking_Length single Revised post-maintenance Cracking Length value
f_Reset_Faulting single Revised post-maintenance Faulting value

The codes for the feasible maintenance treatments for asphalt concrete (AC)-surfaced (flexible & composite) and rigid pavements are described in Table 8.

Table 8. Maintenance Treatment Codes
Treatment Type Code
None 0
AC - Surface Sealing 1
AC - Full Depth Patching 2
AC - Patching with Thin Overlay 3
AC - Major Rehabilitation 4
AC - Reconstruction 5
Rigid - Functional Repair 6
Rigid - Surface Seal with Thin Overlay 7
Rigid - Major Rehabilitation 8
Rigid - Reconstruction 9

The maintenance model uses five lookup tables as shown in Table 9 through Table 13. These tables describe the default values used by the PHT maintenance model including the trigger levels, post-maintenance resets, costs, service life extensions, and feasibility thresholds.

The model will select a preferred treatment strategy from the list in Table 12 and Table 13 based on each option's selection criteria. The model will select the lowest feasible improvement group by order of severity that will address the distress/IRI and RSL conditions.

Table 9. Default Maintenance Trigger Levels
Surface Type Class IRI Cracking Percent Cracking Length Rutting Faulting
Flexible,Composite Interstate 80 0 % 250 ft/mi 0.25 in.  
Flexible,Composite Primary 100 0 % 1000 ft/mi 0.25 in.  
Flexible,Composite Secondary 125 5 % 1000 ft/mi 0.25 in.  
Rigid Interstate 100 0 %     0.10 in.
Rigid Primary 100 0 %     0.10 in.
Rigid Secondary 125 0 %     0.15 in.

Table 10. Default Post-Maintenance Resets (%) and Treatment Costs
Surface Type Treatment IRI Cracking Percent Cracking Length Rutting Faulting Cost per Lane-Mile
Flexible,Composite Surface Sealing 0 % 40 % 15 % 10 %   $ 12,250
Flexible,Composite Full-Depth Patching 0 % 40 % 15 % 25 %   $ 32,500
Flexible,Composite Patching and Overlay 30 % 100 % 90 % 50 %   $ 42,000
Flexible,Composite Rehabilitation 100 % 100 % 100 % 100 %   $ 92,000
Flexible,Composite New / Reconstruction 100 % 100 % 100 % 100 %   $ 290,000
Rigid Functional Repair 50 % 7 %     70 % $ 27,750
Rigid Seal and Overlay 0 % 0 %     0 % $ 22,000
Rigid Rehabilitation 0 % 0 %     0 % $ 132,750
Rigid New / Reconstruction 100 % 100 %     100 % $ 450,000

Note: A value of 0% means no change while a value of 100% implies reset to like-new conditions.


Table 11. Default Service Life Extensions (Years)
Surface Type Treatment RSL Extension Additive (+)
Climate(non-freeze)
Additive (+)
Climate(dry)
Additive (+)
Class(non-principal)
Additive (+)
Pavement(composite)
Additive (+)
Sub-Grade(fine)
Flexible,Composite Surface Sealing 1.5          
Flexible,Composite Full-Depth Patching 0.5 1   2 0 0
Flexible,Composite Patching and Overlay 5.5 0   0 0 0
Flexible,Composite Rehabilitation 10 2.5   2 5 3
Flexible,Composite Reconstruction 20          
Rigid Functional Repair 6 1 2 0   0
Rigid Seal and Overlay 5.5          
Rigid Rehabilitation 15          
Rigid Reconstruction 30          

Table 12. Feasible Improvements for Flexible and Composite (AC) Pavements
  Interstate Primary Secondary
Surface sealing N/A N/A RSL > 5 years
Rutting < 0.35 in
Cracking Length < 2500
Cracking Percent < 5 %
IRI < 150 in/mi
Full depth patching with OR without grinding RSL > 10 years
Rutting < 0.25 in
Cracking Length < 250
Cracking Percent < 5 %
IRI < 125 in/mi
RSL > 5 years
Rutting < 0.25 in
Cracking Length < 1000
Cracking Percent < 5 %
IRI < 150 in/mi
RSL > 5 years
Rutting < 0.35 in
Cracking Length < 1000
Cracking Percent < 5 %
IRI < 125 in/mi
Full depth patching with thin AC overlay OR surface recycling RSL > 10 years
Rutting < 0.35 in
Cracking Length < 1000
Cracking Percent < 10 %
IRI < 125 in/mi
RSL > 5 years
Rutting < 0. 5 in
Cracking Length < 2000
Cracking Percent < 10 %
IRI < 150 in/mi
N/A
Major rehabilitation RSL > 3 years
Rutting < 0.35 in
Cracking Length < 2000
Cracking Percent < 15 %
IRI < 150 in/mi
RSL > 3 years
Rutting < 0.5 in
Cracking Length < 2000
Cracking Percent < 15 %
IRI < 150 in/mi
RSL > 3 years
Rutting < 0.75 in
Cracking Length < 2500
Cracking Percent < 15 %
IRI < 175 in/mi
New or reconstruction RSL < 3 years
Rutting > 0.35 in
Cracking Length > 2000
Cracking Percent > 15 %
IRI > 150 in/mi
RSL < 3 years
Rutting > 0.5 in
Cracking Length > 2000
Cracking Percent > 15 %
IRI > 150 in/mi
RSL < 3 years
Rutting > 0.75 in
Cracking Length > 2500
Cracking Percent > 15 %
IRI > 175 in/mi

Table 13. Feasible Improvements for Rigid Pavements
  Interstate Primary Secondary
Functional repair RSL > 10 yrs
Cracking Percent < 10%
Faulting < 0.15 in
IRI < 125 in/mi
RSL > 10 yrs
Cracking Percent < 10%
Faulting < 0.15 in
IRI < 125 in/mi
N/A
Surface seals & thin overlay RSL > 10 yrs
Cracking Percent < 1%
Faulting < 0.1 in
IRI < 150 in/mi
RSL > 10 yrs
Cracking Percent < 1%
Faulting < 0.1 in
IRI < 150 in/mi
RSL > 10 yrs
Cracking Percent < 1%
Faulting < 0.1 in
IRI < 150 in/mi
Major rehabilitation RSL > 5 yrs
Cracking Percent < 15%
Faulting < 0.2 in
IRI < 175 in/mi
RSL > 5 yrs
Cracking Percent < 15%
Faulting < 0.2 in
IRI < 175 in/mi
RSL > 5 yrs
Cracking Percent < 20%
Faulting < 0.2 in
IRI < 175 in/mi
Reconstruction RSL < 5 yrs
Cracking Percent > 15%
Faulting > 0.2 in
IRI > 175 in/mi
RSL < 5 yrs
Cracking Percent > 15%
Faulting > 0.2 in
IRI > 175 in/mi
RSL < 5 yrs
Cracking Percent > 20%
Faulting > 0.2 in
IRI > 175 in/mi

The PHT maintenance model estimates benefits of each pavement section improvement quantified in terms of the value added to the pavement infrastructure. Benefits are calculated based on the following assumptions:

  • Straight-line depreciation is used to depreciate individual pavement assets over their service life.
  • The post-treatment rate of depreciation remains the same.
  • The initial service life of the pavement is the sum of the current pavement age and the RSL where the current pavement age is the difference between the current year of record and the original year of construction for new pavements; or the year of last improvement for rehabilitated pavements.

Straight-line depreciation, along with the effect of the application of a maintenance treatment on increasing the service life and asset value, is shown in Figure 53.

A dimensionless graph plotting value over time in years illustrates the salient features of straight-line depreciation with maintenance treatment. The depreciation rate is shown as a linear plot falling from left to right, representing change from original construction or rehabilitation to maintenance treatment application, at which point the depreciation rate ramps upward by the increase value post-treatment. This moves the original end of initial service life out in time to a point designated end of extended service life with resumed depreciation.
Figure 53. Straight-Line Depreciation with Maintenance Treatment

The initial value of the pavement at original construction or rehabilitation is determined by the new construction costs multiplied by the adjustment factors shown in Table 14.

Table 14. Initial Pavement Value Adjustment Factors
Pavement Type Surface Type
(Table 15)
Factor
New Pavement 2, 3, 4, 5 1.00
Rehabilitated Pavement, thin overlay 6, 7, 8, 9, 10, 11 0.60
Rehabilitated Pavement, thick overlay 6, 7, 8, 9, 10, 11 0.60

The following equations described how the PHT maintenance model determines the overall cost and benefits of the application of a maintenance treatment.

Determine the initial service life of the pavement.

ISL = (CYR - OCYR) + RSL (New Pavement) (1)
ISL = (CYR - LIYR) + RSL (Rehabilitated Pavement)

Where:
ISL = Initial Service Life, years
CYR = Current Year, (field: year_record)
OCYR = Original Year of Construction, (field: year_last_construction)
LIYR = Year of Last Improvement, (field: year_last_improv)
RSL = Estimated Remaining Service Life, (field f_Overall_RSL_Years).

Estimate monetary benefit of the maintenance action for the highway section.

The term BENEFIT is equal to the expression SLE multiplication factor open parenthesis open parenthesis begin fraction begin numerator NPAC multiplication operator beta end numerator over begin denominator ISL end denominator end fraction close parenthesis plus operator open parenthesis open parenthesis NPAC subtraction operator COST close parenthesis multiplication operator DR close parenthesis close parenthesis multiplication operator open parenthesis LN multiplication operator LEN close parenthesis end expression.

Where:
BENEFIT = Estimated Monetary Benefit
SLE = Service Life Extension, (see Table 11)
NPAC = New Pavement Asset Cost, (see Table 10)
ISL = Initial Service Life, (see Equation 1)
COST = Maintenance Cost, (see Table 10)
DR = Discount Rate
LEN = Length of the Highway Section, miles, (field: section_length)
LN = Number of Lanes, (field: through_lanes)
ß = Adjustment Factor, (see Table 14).

Calculate the total cost of the maintenance action for the highway section.

(3)

Where:
COST = Estimated Cost of Improvements
UCOST = Unit Cost of Improvement per Lane-Mile, (see Table 10)
LEN = Length of the Highway Section, miles, (field: section_length)
LN = Number of Lanes, (field: through_lanes).

Calculate the Benefit-to-Cost Ratio.

The term BCR is equal to the expression open parenthesis begin fraction begin numerator BENEFIT end numerator over begin denominator COST end denominator end fraction close parenthesis end expression.

Where: BCR = Benefit to Cost Ratio
BENEFIT = Estimated Monetary Benefit, (see Equation 2)
COST = Estimated Cost of Improvements (see Equation 3).

Data Aggregations

The PHT tool classifies pavement types as Rigid, Flexible, and Composite. The aggregation of the standard HPMS 2010 surface types into these three classifications is shown in Table 15.

Table 15. Surface Type Classifications
Classification RSL Analysis HPMS Code Description
none No 0 Not Reported
none No 1 Unpaved
Flexible Yes 2 Bituminous
Rigid Yes 3 JPCP - Jointed Plain Concrete Pavement
Rigid No 4 JRCP - Jointed Reinforced Concrete Pavement
Rigid No 5 CRCP - Continuously Reinforced Concrete Pavement
Flexible Yes 6 Asphalt-Concrete (AC) Overlay over Existing AC Pavement
Composite Yes 7 AC Overlay over Existing Jointed Concrete Pavement
Composite No 8 AC (Bi Overlay over Existing CRCP)
Rigid No 9 Unbounded Jointed Concrete Overlay on PCC Pavements
Rigid No 10 Unbounded CRCP Overlay on PCC Pavements
Rigid No 11 Bonded PCC Overlays on PCC Pavements
none No 12 Other

The PHT tool aggregates the standard HPMS 2010 functional classifications for highway sections into three categories of Interstate, Primary, and Secondary roadways as shown in Table 16.

Table 16. Functional System Classifications
Classification HPMS Code Description
Interstate 1 Interstate
Interstate 2 Principal Arterial - Other Freeways and Expressways
Interstate 3 Principal Arterial - Other
Primary 4 Minor Arterial
Primary 5 Major Collector
Secondary 6 Minor Collector
Secondary 7 Local

Parameter Metrics

Table 17 through Table 19 describes the default values for the parameter metrics used by the PHT analysis tool including the terminal thresholds, maximum service life, and default pavement estimates. You may modify any of these values as needed.

Table 17. Default Terminal Values
Surface Type Functional System IRI Cracking Percent Cracking Length Rutting Faulting
Rigid Interstate 170 10 %     0.15 in.
Rigid Primary 220 15 %     0.20 in.
Rigid Secondary 220 20 %     0.20 in.
Flexible Interstate 170 20 % 640 ft/mi 0.40 in.  
Flexible Primary 220 45 % 800 ft/mi 0.60 in.  
Flexible Secondary 220 45 % 1270 ft/mi 0.80 in.  
Composite Interstate 170   100 ft/mi    
Composite Primary 220   60 ft/mi    
Composite Secondary 220   60 ft/mi    

Table 18. Default Maximum Service Life
Treatment Type Years
New HMA 20
New PCC 30
Thick AC Overlay of AC Pavement 10
Thin AC Overlay of AC Pavement 6
Thick AC Overlay of PCC Pavement 10
Unbonded PCC Overlay of PCC Pavement 25
Bonded PCC Overlay of PXX Pavement 15
Thin AC Overlay of AC/PCC Pavement 6

Table 19. Default Pavement Estimates (All Functional Systems)
Pavement Estimate Category State System
On
State System
Off
Last overlay Thickness 3 in. 3 in.
Rigid Pavement Thickness 10 in. 10 in.
Flexible Pavement Thickness 8 in. 8 in.
Base Type Granular Granular
Base Thickness 4 in. 4 in.
Binder Type AC-40 to AC-49 AC-40 to AC-49
Dowel Bar Typically used Typically used
Joint Space 20 feet 20 feet

HPMS 2010 File Format

The following table describes the data fields for the Comma Separated Value (CSV) file for the HPMS2010 formatted data that is used by the PHT analysis tool. This format is defined in the HPMS Field Manual Appendix G, September 2010. Data fields shown in gray are not used in the analysis and can be left blank; but a placeholder must remain in the CSV file for the unused fields for the PHT tool to properly read and import the file.

Table 20. Default Pavement Estimates (All Functional Systems)
001 Year_Record
002 State_Code
003 Route_ID
004 Begin_Point
005 End_Point
006 Section_Length
007 F_System
008 Urban_Code
009 Facility_Type
010 Structure_Type
011 Access_Control
012 Ownership
013 Through_Lanes
014 HOV_Type
015 HOV_Lanes
016 Peak_Lanes
017 Counter_Peak_Lanes
018 Turn_Lanes_R
019 Turn_Lanes_L
020 Speed_Limit
021 Toll_Charged
022 Toll_Type
023 Route_Number
024 Route_Signing
025 Route_Qualifier
026 AADT
027 AADT_Single_Unit
028 Pct_Peak_Single
029 AADT_Combination
030 Pct_Peak_Combination
031 K_Factor
032 Dir_Factor
033 Future_AADT
034 Future_AADT_Year
035 Type_Signal
036 Pct_Green_Time
037 Number_Signals
038 Stop_Signs
039 At_Grade_Other
040 Lane_Width
041 Median_Type
042 Median_Width
043 Shoulder_Type
044 Shoulder_Width_R
045 Shoulder_Width_L
046 Peak_Parking
047 Widening_Obstacle
048 Widening_Potential
049 Curves_A
050 Curves_B
051 Curves_C
052 Curves_D
053 Curves_E
054 Curves_F
055 Terrain_Type
056 Grades_A
057 Grades_B
058 Grades_C
059 Grades_D
060 Grades_E
061 Grades_F
062 Pct_Pass_Sight
063 IRI
064 PSR
065 Surface_Type
066 Rutting
067 Faulting
068 Cracking_Percent
069 Cracking_Length
070 Year_Last_Improv
071 Year_Last_Construction
072 Last_Overlay_Thickness
073 Thickness_Rigid
074 Thickness_Flexible
075 Base_Type
076 Base_Thickness
077 Climate_Zone
078 Soil_Type
079 County_Code
080 NHS
081 Future_Facility
082 STRAHNET_Type
083 Truck
084 VSF
085 Capacity
086 Design_Speed
087 Vertical_Alignment
088 Horizontal_Alignment
089 Volume_Group
090 Expansion_Factor
Updated: 11/22/2013