Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

PUBLICATION NO. FHWA-HRT-22-020 FEBRUARY 2023 

Long-Term Pavement Performance 

Warm-Mix Asphalt Study Final Report, 

Volume III: SPS-10 Nomination Guidelines
FOREWORD

Warm-mix asphalt (WMA), an innovative material that is part of the Federal Highway 

Administration Every Day Counts program, has been implemented by State highway agencies 

throughout the United States. WMA covers a variety of categories, each designed to allow for 

the production and compaction of asphalt concrete at temperatures lower than conventional 

hot-mix asphalt (HMA).

Recognizing that a knowledge gap exists in the comparison of WMA and HMA over the 

performance life of each type of pavement, the Long-Term Pavement Performance (LTPP) 

program initiated this research to design a national experiment to study the performance of 

WMA relative to HMA. New test sections will be recruited into the LTPP program under the 

designation of the specific pavement studies (SPS)-10 experiment called “Warm Mix Asphalt 

Overlay of Asphalt Pavement Study.” 

The purpose of this volume of the report series is to document the guidelines for nominating 

candidate projects and outlines participation requirements for the SPS-10 experiment for the 

LTPP program. This experiment is designed to capture information on the short- and long-term 

performance of WMA relative to HMA. This experiment has been structured to ensure 

consistency and compatibility with the existing LTPP program objectives and database while 

addressing information gaps regarding WMA performance. The intent of the SPS-10 experiment 

is to capture not only field performance but also laboratory test data that will provide both 

user-agencies and researchers a better understanding of the potential benefits of WMA. 

Collectively, this information could be used for performance prediction. 

Mark Swanlund 

Acting Director, Office of Infrastructure

Research and Development

Notice

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

(USDOT) in the interest of information exchange. The U.S. Government assumes no liability for 

the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or 

manufacturers’ names appear in this report only because they are considered essential to the 

objective of the document. 

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve 

Government, industry, and the public in a manner that promotes public understanding. Standards 

and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its 

information. FHWA periodically reviews quality issues and adjusts its programs and processes to 

ensure continuous quality improvement. 
TECHNICAL REPORT DOCUMENTATION PAGE

1. Report No.

FHWA-HRT-22-020

2. Government Accession No. 3. Recipient’s Catalog No.

4. Title and Subtitle

Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume III: SPS-10 Nomination 

Guidelines

5. Report Date

February 2023 

6. Performing Organization Code

7. Author(s)

Jason Puccinelli, Peter Schmalzer, Kevin Senn (ORCID:

0000-0002-9645-5370), Linda McDonald 

8. Performing Organization Report No.

9. Performing Organization Name and Address

NCE

1885 S. Arlington Avenue, Suite 111

Reno, NV 89509

10. Work Unit No.

11. Contract or Grant No.

DTFH61-12-C-00017

12. Sponsoring Agency Name and Address

Office of Infrastructure Research and Development

Federal Highway Administration

6300 Georgetown Pike

McLean, VA 22101-2296

13. Type of Report and Period Covered

Final Report; September 2012–December 2014

14. Sponsoring Agency Code

HRDI-30

15. Supplementary Notes

Jack Springer (HRDI-30) served as the Contracting Officer’s Representative.

16. Abstract

This report provides guidelines and information for nominating candidate projects for the Specific Pavement 

Studies 10 Warm-Mix Asphalt Study and outlines participation requirements. Detailed project nomination forms 

and instructions are included. 

17. Key Words

Asphalt concrete, General Pavement Studies, 

LTPP, pavement, Specific Pavement Studies, 

subgrade, warm-mix asphalt, performance 

monitoring, construction, SPS-10, hot-mix asphalt, 

experiment design

18. Distribution Statement

No restrictions. This document is available to the public 

through the National Technical Information Service, 

Springfield, VA 22161.

https://www.ntis.gov

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

37

22. Price

N/A

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized.
ii
iii

LONG-TERM PAVEMENT PERFORMANCE WARM-MIX ASPHALT STUDY 

PROJECT REPORT SERIES

This volume is the third of six volumes in this research report series. Volume I is the final report, 

and volume II through volume VI contain detailed information about the design and operations 

of the experiment. The following list contains the volumes of this series:

Volume Title Report Number

I Long-Term Pavement Performance Warm-Mix Asphalt 

Study, Volume I: Final Report

FHWA-HRT-22-018 

II Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume II: SPS-10 Experimental 

Matrix and Research Plan

FHWA-HRT-22-019 

III Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume III: SPS-10 Nomination 

Guidelines 

FHWA-HRT-22-020 

IV Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume IV: SPS-10 Materials 

Sampling and Testing Requirements 

FHWA-HRT-22-021 

V Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume V: SPS-10 Performance 

Monitoring Guide

FHWA-HRT-22-022 

VI Long-Term Pavement Performance Warm-Mix Asphalt 

Study Final Report, Volume VI: SPS-10 Construction 

Documentation Guide 

FHWA-HRT-22-023 
iv

TABLE OF CONTENTS

CHAPTER 1. PARTICIPATION AND PROJECT SELECTION .......................................... 1

Participation Requirements ................................................................................................... 1

Project Selection Criteria ....................................................................................................... 2

CHAPTER 2. NOMINATION PROCEDURE AND FORMS ................................................. 5

Nomination Procedure............................................................................................................ 5

Nomination Forms .................................................................................................................. 5

Sheet A. General Project Information .................................................................................. 6

Sheet B. Pavement Design Information, Resurfacing........................................................ 12

Sheet C. Mix Information..................................................................................................... 19

Sheet D. Test Section Layout ............................................................................................... 24

CHAPTER 3. TRAFFIC DATA COLLECTION GUIDELINES .......................................... 27

Equipment Location ............................................................................................................. 27

Equipment Type .................................................................................................................... 27

Equipment Calibration ......................................................................................................... 27

Traffic Data Types and Collection Frequency ................................................................... 28

Traffic Data Submittal ......................................................................................................... 28

Sheet 10: Traffic Volume and Load Estimate Update—No Site Count ........................... 29

REFERENCES ............................................................................................................................ 31
v

LIST OF TABLES

Table 1. Final experimental matrix for SPS-10. ............................................................................. 5

Table 2. Pavement surface material type classification codes. ..................................................... 16

Table 3. Base and subbase material type classification codes. ..................................................... 16

Table 4. Bituminous bound base and subbase material type classification codes. ....................... 17

Table 5. Fine-grained subgrade material type classification codes. ............................................. 17

Table 6. Coarse-grained subgrade material type classification codes. ......................................... 17

Table 7. Thin seal and interlayer material type classification codes. ........................................... 18
vi

LIST OF ABBREVIATIONS

AADT annual average daily traffic

AASHTO American Association of State and Highway Transportation Officials

AC asphalt concrete

ESAL equivalent single axle load 

FHWA Federal Highway Administration

GPS global positioning system 

HMA hot-mix asphalt

LTPP Long-Term Pavement Performance

MEPDG Mechanic-Empirical Pavement Design Guide

PCI pavement condition index

PG performance-graded 

RAP recycled asphalt pavement

RSC regional support contractor 

SHRP Strategic Highway Research Program

SPS Specific Pavement Studies

WIM weigh-in-motion 

WMA warm-mix asphalt 
1

CHAPTER 1. PARTICIPATION AND PROJECT SELECTION

This report provides guidelines and information for nominating candidate projects for the 

Long-Term Pavement Performance (LTPP) program Specific Pavement Studies (SPS)-10 WarmMix Asphalt (WMA) experiment and outlines participation requirements. Detailed project 

nomination forms and instructions are included in this report. Details of the experimental design 

and study factors are described in volume II of this report series (Puccinelli et al. 2022).

PARTICIPATION REQUIREMENTS

State and provincial highway agencies considering participating in the SPS-10 experiment must 

be willing to perform the following activities:

• Construct the test sections described in the experimental design document found in 

volume II (Puccinelli et al. 2022). Test sections to be constructed include one section 

using conventional hot-mix asphalt (HMA) designed according to the agency’s current 

mix design and two sections using different WMA technologies. All test sections on a 

project must be constructed during the same construction season. The treatments within 

the length of the test sections must be applied across all lanes in the direction of travel.

• Provide traffic information. For an SPS-10 section, a continuously operating permanent 

device for classification and weight data is preferred. This level of data collection is 

desired for two reasons: to provide the accurate traffic loading measurements required to 

develop mechanistic and mechanistic/empirical design models and to provide the base 

data necessary to understand the intricacies of the interactions among pavement, traffic 

load, and environment. 

 Although data collection on the site continuously over the year is preferred, sites without 

continuous weigh-in-motion (WIM) equipment will still be considered. The minimum 

recommended data collection effort for each site is 2 w of continuous classification data 

4 times per year (a total of 8 w of classification data per year). It is the agency’s 

responsibility to ensure collected data are representative and account for seasonal 

variation, weekday/weekend differences, and inconsistent truck loading patterns 

throughout the year. Complete details on traffic data collection can be found in chapter 3 

of this report. 

 When nominating a project location, the location of existing WIM equipment should be 

considered. Sites where existing WIM equipment can be used to capture the traffic 

loading would allow for traffic data to be captured without the installation of additional 

equipment. 

• Perform and/or provide for drilling, coring, and sampling of in-place pavement materials 

used in the test sections. Costs for this work are to be borne by the participating agency. 

LTPP regional support contractor (RSC) staff will be onsite to perform sample logging 

and sample shipment. Testing of samples will be performed by the Federal Highway 

Administration (FHWA) or its contractors.
2

• Prepare plans, specifications, quantities, and all other documents necessary as part of the 

agency’s contracting procedure. The agency must also provide construction control, 

inspection, and management in accordance with its standard quality control and assurance 

procedures. RSC staff will be onsite during construction to perform documentation 

required by LTPP.

• Provide periodic traffic control for onsite data collection activities, such as drilling and 

materials sampling, distress surveys, deflection testing, and other monitoring activities.

• Coordinate maintenance activities on the test sections to prevent application of premature 

treatments that alter the characteristics of the test sections and limit their use in the study.

• Notify FHWA LTPP RSC before the application of overlays or other such treatments 

when any of the test sections reach an unsafe condition or become a candidate for 

rehabilitation. As much lead time as possible is needed to allow recording of the terminal 

condition of the test sections. 

• Provide and maintain signing and marking of test sites.

If State or provincial highway agency personnel would like to discuss the details of these 

participation requirements, they should contact the LTPP RSC for their region. 

PROJECT SELECTION CRITERIA

The following criteria will be considered in evaluating candidate projects for inclusion in this 

experiment:

• The construction project must be of sufficient length to accommodate all the 

experimental test sections. The experimental design requires a minimum of 243.8 m 

(800 ft) per section, with a core monitoring section of 152.4 m (500 ft) that will be used 

for future nondestructive performance monitoring. A 15.2-m (50-ft) buffer on each side 

of the monitoring area will be included to separate the destructive sampling area from the 

monitoring area. The destructive sampling area will consist of 30.5 m (100 ft) on each 

side of the monitoring area. The sampling area will be built at the same time and to the 

same specifications as the monitoring area to allow material sampling without disturbing 

the 152.4-m (500-ft) monitored area and will consist of the outside lane (i.e., truck lane) 

only. Transition zones are required between test sections and must be a minimum of 

2,483.8 m (800 ft) long. The project will require at least three different mixes (one HMA 

and two WMA) to be produced at the same plant. Each mix may be placed on the test 

section only after the plant has reached steady-state operation, which may require long 

transitions between the sections, use of the mix for some other purpose, or disposal of the 

mix before the plant achieves steady-state operation. The contractor must establish rolling 

patterns/compactive effort requirements to meet construction specifications. The 

minimum project length is 1,219 m (4,000 ft) but may be longer if more than the 

minimum number of sections are built or if the transition zones are longer than the 

minimum length. The same compaction equipment must be used on all three test sections.
3

• Other than the mix properties of the surface layer, all other properties of the test sections 

should be as similar as possible. If the construction project is a resurfacing project, 

variation in the preconstruction condition, pavement layer thicknesses, and subgrade 

properties should be minimal. Areas with unusual distress types should be avoided. 

• Traffic flow over all the test sections on a project should be uniform. All sections should 

carry the same traffic stream. Intersections, rest stops, on-off ramps, weaving areas, 

quarry entrances, and so forth should be avoided on and between test sections on a 

project.

• Test sections should be located on portions of the project that are relatively straight and 

have a uniform vertical grade. Horizontal curves greater than 3 degrees and vertical 

grades greater than 4 percent should be avoided. 

• It is highly desirable that the portion of the project that includes the proposed test sections 

be opened to traffic at the same time.

• Ideally, all test sections should be located on shallow fills. The entire length of each test 

section, however, should be located completely on either a cut or a fill. Cut-fill transitions 

and side hill fills should be avoided. 

• Culverts, pipes, and other substructures beneath the pavement should be avoided within 

the limits of each test section. It is recommended that subsurface structures, if required, 

be located in the transition zones between test sections.

• Pavements that are excessively underdesigned or overdesigned for existing site 

conditions should be avoided. As a general guide, the design life should be between 

10 and 20 yr, as determined using the agency’s standard design procedure. The accepted 

range of overlay thicknesses is 51 to 102 mm (2 to 4 inches).

• Any open-graded friction courses or surface treatments (i.e., chip seals, slurry seals) 

should be removed via milling before the SPS-10 overlay is placed.

• Pre-overlay repairs may be performed in accordance with the State or provincial highway 

agency’s standard practice. The repairs should be consistent throughout the project so as 

not to add variability between test sections.

• Tack coats must be used between lifts and between the original surface and overlay.

• Road sections that have been widened or those with added lanes or added shoulders are 

not desirable for the SPS-10 experiment. 

• Existing pavements with retrofitted edge drains are not desirable.

• The project must not have a curb and gutter within 1.8 m (6 ft) of the outside edge of the 

pavement adjacent to the test lane.
4

• The test sections should be placed in the outside test lane and must be 3.7 m (12 ft) wide 

with a consistent and uniform thickness. 

• The type, extent, and severity of distress should be relatively uniform over the project. 

Test sections must be located to avoid areas of unusual distress occurrences on the 

project. It is desired that the type of distress and performance of the pavement are typical 

for the agency. Unique performance and deterioration should be avoided to the extent 

possible.

By minimizing the influence of other factors (such as changes in the existing pavement structure, 

subgrade, traffic patterns, and drainage characteristics), these criteria and considerations will 

help identify projects in which the relative performance of the test sections is due to the 

differences in the asphalt concrete (AC) mix of the surface layer.

Section homogeneity is important to the success of the experiment. For resurfacing projects, 

homogeneity includes the subgrade, existing pavement structure, and existing condition. 

Construction history records, while valuable, often do not fully reflect the variability of 

in-service pavements. It is requested that the agency evaluate the homogeneity of potential 

projects before nominating them and include the evaluation results with its submission. Tools to 

evaluate homogeneity include distress surveys, falling weight deflectometer testing, and 

ground-penetrating radar testing. 

It is recognized that projects containing all of the desirable characteristics are not always readily 

available. Each candidate site will be evaluated individually to determine the extent of 

compliance with the desired criteria and usefulness to the experiment. Deviation from the desired 

project characteristics may be necessary to obtain sufficient projects for the experiment. For 

example, projects will be considered where it is not possible to locate all of the test sections 

completely in either cuts or fills. In this case, it may be necessary to locate some test sections in 

cuts and others in fills. Also, on a project in rolling terrain with limited distance between 

intersections, it may be necessary to locate a test section over a shallow cut-fill transition (less 

than 3 m [9.8 ft] difference). Generally, engineering judgment will be used to evaluate the impact 

of such nonuniformities on test section performance. 

The criteria and considerations presented in this document will be used to evaluate and rank 

candidate projects in cases where more than the required number of projects are available. They 

can also be used as a guide by an agency to identify candidate projects in its jurisdiction that are 

most suitable for nomination.

Special consideration will be given to projects that include test sites that are located near existing 

SPS or General Pavement Studies experiments. 
5

CHAPTER 2. NOMINATION PROCEDURE AND FORMS

NOMINATION PROCEDURE

State or provincial highway agencies desiring to participate in the SPS-10 experiment should 

review candidate projects and evaluate them against the criteria and considerations presented in 

this document. A minimum of two test sites is being sought for each row in table 1, the final 

experimental matrix for SPS-10. Under certain conditions, additional projects might be included 

in one or more of the experimental design cells, as represented by the rows of table 1. 

Table 1. Final experimental matrix for SPS-10. 

Moisture Temperature Traffic

Number of 

Projects

Wet Freeze High 2 

Wet Freeze Low 2 

Wet No freeze High 2 

Wet No freeze Low 2 

Dry Freeze High 2 

Dry Freeze Low 2 

Dry No freeze High 2 

Dry No freeze Low 2 

Note: Projects consist of an HMA control section and two different 

WMA categories (foaming process and chemical). 

Project acceptance will be performed sequentially over time. Decisions on acceptance will be 

made by the “Latest Date for Approval Notification from FHWA” to be furnished by the 

nominating agency on the nomination forms contained in this document. Nominating agencies 

should set this date as late as possible to allow for review of other projects nominated for the 

same experiment design cell and selection of the best-suited sites for this experiment. Agencies 

should coordinate their nomination of projects through FHWA LTPP RSC.

NOMINATION FORMS

The following are instructions for completion of the SPS-10 candidate project nomination and 

instruction forms. Each form is referenced according to a sheet letter designation.
6

SHEET A. GENERAL PROJECT INFORMATION

This sheet includes information on project location, significant dates, and design traffic. 

State/Province

Enter the State or province in which the project is located.

SHRP ID

FHWA will assign this four-digit Strategic Highway Research Program (SHRP) identifier if the 

project is selected for inclusion in the SPS-10 experiment and will be used as a project reference 

number. 

Project Location 

This portion of the form provides information on the location of the candidate project. In this 

document, a project refers to the overall construction project. Test sections refer to 152.4-m 

(500-ft) portions of the project in which the experimental pavement structures are constructed 

and monitored over time. 

Route Number

Enter the number assigned to the route on which the project is located. The common number 

used on maps and highway signs should be provided to avoid confusion. 

Route Signing

Check the appropriate designation for the route on which the project is located. If the project is 

located on a road other than an interstate, U.S., State, or county route, please write in the 

appropriate designation in the space provided with a short explanation. For example, a farm-tomarket signed route should be entered as “FM—Farm to Market.” This designation should refer 

to how the route is signed and indicated on general highway maps. 

Project Location

Enter the start and end mileposts or milepoints of the portion of the project that is considered 

suitable for the construction of the test sections. Mileposts or milepoints refer to reference 

locations signed or marked along the route in the field. If the route is signed with kilometer 

posts, enter the appropriate kilometer post numbers (scratch out milepost and write kilometer 

post on the form). The start and end station locations are not required but are requested for use in 

locating the portion of the project proposed for the experimental sections on the plans. 

Location Description

Provide a written description of the location of the start of the project referenced to permanent 

landmarks, such as signed highway intersections, signed or labeled bridges, underpasses, 

overpasses, rest areas, and railroad crossings. The objective is to provide a reference for field 
7

crews to locate the section in the field easily. Distances from a landmark located before the 

section (in the direction of travel) and a landmark located after the start of the section should be 

specified. For example, “The start of the project is 2.2 km north of overpass 20-45-43; the 

intersection with I–71 is located 3.3 km north of the start of the project” (assuming the direction 

of travel is northbound). 

GPS Coordinates

Enter the global positioning system (GPS) latitude and longitude coordinates (in degrees, 

minutes, and seconds to the nearest tenth of a second [0.1”]) of the location of the start of the 

project.

Direction of Travel

Check the box that describes the direction of travel of the lane proposed for the LTPP 

experiment. The direction of travel should be as the route is signed. For example, if the lane is on 

I–71, only northbound or southbound should be chosen, even if the route trends mostly east-west 

within the project limits.

Facility Type

Check the box “Divided” if there is a median, curb, or another permanent barrier between the 

directions of traffic.

Number of Lanes

For an undivided road, enter the total number of lanes in both directions. For a divided road, 

enter the number of lanes in the project direction.

County

Enter the county or county-level governmental jurisdiction unit in which the project is located. If 

the project is located in more than one county, indicate the county first encountered in the 

direction of travel.

Highway Agency District Number

Enter the number that identifies the highway agency’s district, division, or region in which the 

project is located.

Distance to Nearest Weather Station

Enter the distance in miles to the nearest fully operational and permanent weather station. The 

weather stations operated by the National Oceanic and Atmospheric Administration and the 

National Weather Service are preferred.
8

Significant Dates

Latest Date of Approval Notification from FHWA

Enter the latest date that FHWA can notify the agency of acceptance of a project into the 

experiment. This date represents the latest date that an agency can start the preparation of 

construction specifications and contractual documents to have the test sections constructed. This 

date should be a realistic absolute latest date that provides FHWA with the longest time possible 

to evaluate and coordinate other candidate projects so that the best geographical spread and most 

suitable projects are included in the experiment.

Contract Letting Date

Enter the actual date the contract is scheduled for letting.

Estimated Construction Start Date

Enter the date on which construction on the portion of the project containing the test sections is 

expected to begin. This date is important for scheduling preconstruction activities, such as 

section marking, deflection tests, and so forth. 

Estimated Date Test Sections Opened to Traffic

Indicate the expected date on which the test sections will be opened to traffic.

Estimated Construction Completion Date

Enter the scheduled date for completion of construction of the project on which the LTPP test 

sections are located. In some instances, the estimated dates for opening the test sections to traffic 

and for completion of construction will be the same.

Traffic

AADT (in project lane) 

Enter the estimate of the annual average daily traffic (AADT) for all vehicles in the project lane 

only. 

Percent Heavy Trucks and Combinations

Enter the ratio of trucks and heavy combinations to total vehicles (AADT) expressed to the 

nearest tenth of a percent. This count excludes all pickups, panels, and other two-axle, four-tire 

trucks. This number is for the traffic in the project lane only.

Annual 18-kip ESALs (in project lane)

Provide the design average application rate of heavy truck loadings, in 18-kip equivalent single 

axle load (ESAL) applications, in the study lane of the proposed project. The value should be the 

design number of ESAL applications divided by the duration of the design period. 
9

Design Life (years)

Enter the length of the design life, in years, used for estimating the traffic used in the pavement 

design of the project. 

Traffic Equipment

Permanent WIM installed that can be applied to test sections? (Y or N)

Indicate whether an existing permanent WIM is installed within close proximity to the proposed 

location. The WIM must be in the same direction of travel and have the same traffic 

loadings/patterns as the site location.

WIM Location

Provide the milepost and direction of travel of the installed WIM.

WIM Type/Manufacturer

Provide information on the type of WIM equipment installed.

Last Calibration Date of WIM

Provide the date of the last known calibration of the WIM equipment. 

Does agency agree to provide a minimum of 2 w of classification data, 4 times per year 

(total 8 w)?

If a permanent, full-time WIM is not currently available for the proposed location, please 

indicate whether the agency is willing to collect temporary classification data for 2 w, 4 times 

per year. 
Sheet A. SPS-10 Candidate Project Nomination and Information

STATE/PROVINCE: 

SHRP ID: (to be assigned by FHWA if project is selected)

10

General Project Information

Project Location 

Route Number 

Route Signing ☐ Interstate ☐ U.S. ☐ State ☐ County 

☐ Other 

Project Location Start Milepost End Milepost 

Begin Station End Station 

Location Description

GPS Coordinates Latitude Longitude 

Direction of Travel ☐ North Bound ☐ South Bound ☐ West Bound ☐ East Bound 

Facility Type ☐ Divided ☐ Undivided 

Number of Lanes (total # 

in both directions if 

undivided) 

County 

Highway Agency District 

Number 

Distance to nearest 

Weather Station (miles)

Project Type

☐ New Construction ☐ Flexible Resurfacing ☐ Rigid Resurfacing

Significant Dates

Latest Date of Approval Notification from FHWA 

Contract Letting date

Estimated Construction Start Date

Estimated Date Sections Opened to Traffic

Estimated Construction Completion Date

Traffic

AADT (in project lane)

Percent Heavy Trucks and Combinations 

Annual 18-kip ESALs (in project lane)

Design Life (years)
Sheet A. SPS-10 Candidate Project Nomination and Information

STATE/PROVINCE: 

SHRP ID: (to be assigned by FHWA if project is selected)

11

Traffic Equipment

Permanent WIM installed that can be 

applied to test sections? (Y or N) 

WIM Location: Milepost: Direction of Travel: 

WIM Type/Manufacturer:

Last Calibration Date of WIM:

Does Agency agree to provide a minimum 

of 2 weeks of classification data, 4 times 

per year (total 8 weeks)? (Y or N)

 
12

SHEET B. PAVEMENT DESIGN INFORMATION, RESURFACING

The purpose of this sheet is to provide information on the State or provincial highway agency’s 

typical pavement resurfacing design for the project site. Information should represent the 

pavement structure for the project as a whole, without special consideration of the test sections 

(i.e., what the agency would construct if the project is not included in the SPS-10 experiment). 

State/Province

Enter the State or province in which the project is located.

SHRP ID

FHWA will assign this four-digit SHRP identifier if the project is selected for inclusion in the 

SPS-10 experiment and will be used as a project reference number.

Design Method

If this project was designed using the Mechanistic-Empirical Pavement Design Guide (MEPDG) 

(AASHTOWare Pavement ME Design) (AASHTO 2020) or the American Association of State 

Highway and Transportation Officials (AASHTO) 1993 design procedure (AASHTO 1993), 

check the appropriate box. Otherwise, describe the design method in the space provided. 

Design Life

Enter the design life of the pavement structure in years.

Existing Pavement Condition

Enter the condition of the existing pavement. If available, please provide the pavement condition 

index (PCI) as determined using ASTM D6433 (ASTM 2020). If another methodology was used, 

please describe it in the space provided for “Other.” If no objective description of the pavement 

condition is available, please describe it as good, fair, or poor. 

Predominant Distress Type

Enter the most significant distress on the section, and the distress of most importance in 

determining the need for resurfacing and the design of the resurfacing. For example, if the 

section exhibits both alligator cracking and weathering, alligator cracking should be entered here. 

Date Existing Surface Opened to Traffic

Enter the date the existing surface layer was placed. Consider only structural layers and ignore 

fog seals and surface treatments.
13

Design Layer Structure

Layer Number

This layer number convention starts with the naturally occurring subgrade as layer 1 and 

progresses to the pavement surface as the highest numbered layer. Each unique material above 

the subgrade is assigned a layer number and corresponding material type code. Fabrics, surface 

treatments, and other thin layers should be included. 

Layer Description

Describe the layer in general terms. Examples include “select fill,” “aggregate base,” and “hot 

mix.” Please use generally understood terms and avoid agency-specific descriptions.

Material Type Class Code

The two-digit codes identifying the type of material in each layer of the pavement structure are 

shown in table 2 through table 7. The intent is a general identification of materials for 

classification and project selection purposes. 

Thickness (inches)

Enter the thickness of the existing layer in inches. Provide the full thickness of the layer as it 

exists preconstruction, even for layers that will be reduced in thickness or removed entirely 

during construction. 

Required Overlay Thickness (inches)

Enter the thickness of the required overlay to meet the design life, as determined using the 

pavement design methodology used. Please do not round up the thickness. The intent is to obtain 

the actual thickness of pavement materials required to meet the design life to the precision 

provided by the pavement design method used. 

Design Overlay Thickness (inches)

Enter the thickness of overlay material that the agency intends to specify in construction 

documents. Typically, this will be the required thickness rounded up to reflect actual 

construction practices.

Depth of Milling/Grinding (inches)

Enter the depth of milling/grinding (if any) of the existing pavement surface.

Estimated Base Repair Quantity (percent)

Enter the percentage of the area of the project that will require base repairs or other excavation 

below the postmilling surface.
14

Other Preconstruction Repairs

Describe any other pre-overlay repairs that the agency intends to perform other than 

milling/grinding and base repair.
Sheet B. SPS-10 Candidate Project Nomination and Information 

STATE/PROVINCE:

SHRP ID: (to be assigned by FHWA if project is selected)

15

Pavement Design Information

Resurfacing

Design Method ☐ MEPDG ☐ AASHTO 93 ☐ Other 

Design Life (years)

Existing Pavement Condition

Condition Assessment Method ☐ PCI (ASTM D6433) ☐ Other 

Predominant Distress Type:

Date Existing Surface Opened to 

Traffic:

Existing Layer Structure

Layer No.1 Layer Description Material Code2 Thickness (in)3

1 Subgrade

2 

3 

4 

5 

6 

7 

8 

9 

Notes:

1. Layer 1 is the naturally occurring subgrade soil. The pavement surface will have the largest assigned layer 

number

2. Refer to Tables 2 through 7 for material class codes

3. If the depth to a rigid layer (such as bedrock) is known, enter it here. Otherwise leave blank.

Required Overlay Thickness (in)

Design Overlay Thickness (in) 

Depth of Milling/Grinding (in)

Estimated Base Repair Quantity (%)

Other Pre-Construction Repairs
16

Table 2. Pavement surface material type classification codes.

Material Type Code

Hot-mixed, hot-laid AC, dense-graded 01 

Hot-mixed, hot-laid AC, open-graded (porous friction course) 02 

Sand asphalt 03 

Jointed plain portland cement concrete 04 

Jointed reinforced portland cement concrete 05 

Continuously reinforced portland cement concrete 06 

Prestressed portland cement concrete 07 

Fiber-reinforced portland cement concrete 08 

Plant-mix, cold-laid emulsified asphalt material 09 

Plant-mix, cold-laid cutback asphalt material 10 

Single surface treatment 11 

Double surface treatment 12 

Hot-recycled central plant mix AC 13 

Central plant-mix, cold-laid recycled AC 14 

Mixed-in-place, cold-laid recycled AC 15 

Heater scarification/recompaction recycled AC 16 

Jointed plain recycled portland cement concrete 17 

Jointed reinforced recycled portland cement concrete 18 

Other 19 

Table 3. Base and subbase material type classification codes.

Material Type Code

No base (pavement directly on subgrade) 21 

Uncrushed gravel 22 

Crushed stone, gravel, or slag 23 

Sand 24 

Soil–aggregate mixture, predominantly fine-grained soil 25 

Soil–aggregate mixture, predominantly coarse-grained soil 26 

Soil cement 27 

Cement aggregate mixture 37 

Lean concrete (<3 sacks/yd3) 38 

Recycled portland cement concrete 39 

Sand–shell mixture 40 

Limerock, caliche (soft carbonate rock) 41 

Lime-treated subgrade soil 42 

Cement-treated subgrade soil 43 

Pozzolanic–aggregate mixture 44 
17

Table 4. Bituminous bound base and subbase material type classification codes.

Material Type Code

Dense-graded, hot-laid, central plant mix 28 

Dense-graded, cold-laid, central plant mix 29 

Dense-graded, cold-laid, mixed-in-place 30 

Open-graded, hot-laid, central plant mix 31 

Open-graded, cold-laid, central plant mix 32 

Open-graded, cold-laid, mixed-in-place 33 

Recycled AC, plant mix, hot-laid 34 

Recycled AC, plant mix, cold-laid 35 

Recycled AC, mixed-in-place 36 

Sand asphalt 46 

Table 5. Fine-grained subgrade material type classification codes.

Material Type Code

Clay (liquid limit >50) 51 

Sandy clay 52 

Silty clay 53 

Silt 54 

Sandy silt 55 

Clayey silt 56 

Table 6. Coarse-grained subgrade material type classification codes.

Material Type Code

Sand 57 

Poorly graded sand 58 

Silty sand 59 

Clayey sand 60 

Gravel 61 

Poorly graded gravel 62 

Clayey gravel 63 

Shale 64 

Rock 65 
18

Table 7. Thin seal and interlayer material type classification codes.

Material Type Code

Chip seal coat 71 

Slurry seal coat 72 

Fog seal coat 73 

Woven geotextile 74 

Nonwoven geotextile 75 

Stress-absorbing membrane interlayer 77 

Dense-graded AC interlayer 78 

Aggregate interlayer 79 

Open-graded AC interlayer 80 

Chip seal with modified binder (excluding absorbing membrane) 81 

Sand seal 82 

Asphalt rubber seal coat (stress-absorbing membrane) 83 

Sand asphalt 84 

Other 85 
19

SHEET C. MIX INFORMATION

The purpose of this sheet is to provide information on the AC mixes that the agency intends to 

use as part of the experiment. Mixes used on portions of the project outside the section 

boundaries are not relevant to this form.

State/Province

Enter the State or province in which the project is located.

SHRP ID

FHWA will assign this four-digit SHRP identifier if the project is selected for inclusion in the 

SPS-10 experiment and will be used as a project reference number.

General Mix Design Information

The information required for this section will be the same for the HMA mix and the two core 

section WMA mixes.

Nominal Maximum Aggregate Size (millimeters)

Enter the nominal maximum aggregate size of the mixes in millimeters.

RAP Content (percent)

Enter the quantity of recycled asphalt pavement (RAP) to be used in the mixes, expressed in 

terms of binder replacement as percent by total binder in the mix.

Rubber Content (percent)

Enter the quantity of rubber to be used in the mixes, expressed as percent by total binder in the 

mix.

Total Binder Content (percent)

Enter the total quantity of binder, including virgin binder, binder from RAP, and rubber, 

expressed as percent by total weight of mix.

Mix-Design Method

Enter the mix-design method that the agency intends to use. If Superpave, check the box 

provided. Otherwise, check “Other” and enter the mix-design method in the space provided.

HMA Control Section

The information in this section applies to the HMA control section only. 
20

Binder Grade

Enter the binder grade to be used on the HMA control section. If this is a performance-graded 

(PG) binder, check the box provided. Otherwise, check “Other” and enter the name of the 

grading system. 

WMA Sections

The information in these sections applies to the two core WMA sections only. 

WMA Technology

Check the appropriate box for the WMA technology to be used on the section. 

Additive Type

Describe the specific type of additive to be used. Use trade names as appropriate. Leave this 

space blank if a foaming process is to be used.

Additive Dosage Rate 

Enter the dosage rate of the additive, including the basis of measurement (e.g., “percent by 

weight of mix” or “percent by weight of binder”). Leave this space blank if a foaming process is 

to be used. 

Supplemental Sections

If the agency intends to build supplemental sections, enter the relevant information in the places 

provided. 

WMA Technology

Check the appropriate box for the WMA technology to be used on the section. 

Additive Type

Describe the specific type of additive to be used. Use trade names as appropriate. Leave this 

space blank if a foaming process is to be used.

Additive Dosage Rate

Enter the dosage rate of the additive, including the basis of measurement (e.g., “percent by 

weight of mix” or “percent by weight of binder”). Leave this space blank if a foaming process is 

to be used. 
21

Other Variations

If variations from the information specified in Sheets A, B, or C are intended for this section, 

describe them here. Examples include variation in RAP content, variation in binder content or 

grade, or variation in overlay thickness. 
Sheet C. SPS-10 Candidate Project Nomination and Information 

STATE/PROVINCE: 

SHRP ID: (to be assigned by FHWA if project is selected)

22

Mix Information 

General Mix Design Information 

Nominal Maximum Aggregate Size, mm

RAP Content, %

Rubber Content, %

Total Binder Content, % 

Mix Design Method ☐ Superpave ☐ Other 

HMA Control Section

Binder Grade

Binder Grade Basis ☐ PG ☐ Other 

WMA Section 1

WMA Technology ☐ Foaming Process ☐ Chemical Additive

Additive Type 

Additive Dosage Rate

WMA Section 2

WMA Technology ☐ Foaming Process ☐ Chemical Additive

Additive Type 

Additive Dosage Rate

☐ Supplemental Section 1

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation

☐ Supplemental Section 2 

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation
Sheet C. SPS-10 Candidate Project Nomination and Information 

STATE/PROVINCE: 

SHRP ID: (to be assigned by FHWA if project is selected)

23

☐ Supplemental Section 3 

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation

☐ Supplemental Section 4 

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation

☐ Supplemental Section 5 

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation

☐ Supplemental Section 6 

WMA Technology ☐ Foaming Process ☐ Foaming Additive ☐ Chemical Additive 

☐ Organic Additive

Additive Type 

Additive Dosage Rate

Other Mix Variation

Note: If more than 6 supplemental sections are built, the section numbers will change from “2 to 

6” to “7 to 11,” continuing the process to cover each supplemental section. 
24

SHEET D. TEST SECTION LAYOUT

This sheet includes detail on the layout of the LTPP experimental test sections.

State/Province

Enter the State or province in which the project is located.

SHRP ID

This four-digit SHRP identifier will be assigned by FHWA if the project is selected for inclusion 

in the SPS-10 experiment and will be used as a project reference number.

Test Section Layout 

Total Number of Test Sections

Enter the total number of test sections planned for the project, including the three core sections 

and any supplemental sections.

Number of Test Sections on Cut and Fill

The as-built plan and profile sheets for the candidate project should be reviewed to determine the 

nature of the suitable locations for the test sections. It is preferred that all test sections be located 

entirely in either a fill or a cut. Potential test sections should be 243.8 m (800 ft) long to enable 

sampling of the subgrade and the pavement materials without disturbing the 152.4-m (500-ft) 

long monitored sections. If all test sections can be located completely in a cut or fill, place a 

checkmark on the appropriate line. If it is not possible to locate all test sections entirely in fills or 

cuts and it is necessary to locate some test sections in cuts and some in fills within the project, 

indicate the number of potential locations in cuts and the number of potential locations in fills. 

Maximum Transition Between Test Sections

Indicate the maximum transition (in feet) possible between consecutive test sections to locate all 

the test sections within the project limits.

Vertical Grade

Enter the average vertical grade slope, in percent, for the portion of the project on which the test 

sections are located. Downgrades (in the direction of travel) should be indicated as a negative 

value. If the test sections are located on varying slopes, provide information under “Comments 

on Deviations from Desired Site Location Criteria” on the range of differences in the vertical 

slopes between the test section sites.

Horizontal Curvature

Check the box if the test sections are located on a tangent section or indicate the horizontal 

degree of curvature at the test site. Provide a brief description under “Comments on Deviation 

from Desired Site Location Criteria” if some sections are located on tangents and others on 
25

horizontal curves. Provide information on any differences in the cross slopes of test sections due 

to superelevations on horizontal curves.

Comments on Deviations from Desired Site Location Criteria

Provide brief comments describing significant deviations from the desired site location criteria 

presented in this document. Include in these comments items such as the following:

• Unusual traffic patterns.

• Intersections between test sections.

• Substructures beneath test sections.

• Test section locations at cut–fill transitions.
Sheet D. SPS-10 Candidate Project Nomination and Information 

STATE/PROVINCE:

SHRP ID: (to be assigned by FHWA if project is selected)

26

Test Section Layout

Total Number of Test Sections 

Number of Test Sections Entirely on: Cut Fill 

Maximum Transition Between Consecutive Test Sections, feet 

Average Vertical Grade, % (+ upgrade, - downgrade) 

Horizontal Curvature, degrees: ☐ Tangent

Comments on Deviations from Desired Site Location Criteria
27

CHAPTER 3. TRAFFIC DATA COLLECTION GUIDELINES

This chapter contains traffic data collection guidelines for the SPS-10 experiment. Quality traffic 

data are critical in assessing the vehicle loading on pavements. To quantify traffic loading, LTPP 

uses vehicle volume by classification data to determine the number of heavy and light vehicles 

using a roadway, as well as the variability in volume during different periods (time of day, day of 

week, and time of year). Individual vehicle weight data are summarized to determine the 

distribution of axle weights by class of vehicle. When combined, these datasets provide the 

necessary information to measure or estimate vehicle loads directly at test sites.

EQUIPMENT LOCATION

Traffic data must be collected at or near the WMA test site in the same direction of travel and in 

the LTPP lane. If the equipment is not located at the site, it should be in close proximity to the 

WMA test site, either upstream or downstream. The intent is to measure the same vehicles that 

cross over the test site, so the traffic data collection equipment must be placed away from 

interchanges and off-ramps or on-ramps between the equipment location and the SPS-10 project. 

EQUIPMENT TYPE

The individual State or provincial highway agency will determine the type of sensor to use to 

collect the traffic data at each test site. The Transportation Research Board LTPP Expert Task 

Group on Traffic Data Collection and Analysis strongly recommends using permanently 

mounted sensors whenever possible, even when only short-duration counts are being taken. The 

LTPP SPS Traffic Data Collection Pooled-Fund Study has demonstrated that correctly installed 

and maintained permanent equipment yields more reliable results, particularly for WIM data

(Walker 2012). Permanent equipment also reduces the cost of repeated equipment setup, allows 

for longer data collection efforts, requires less staff time per data collection session, and reduces 

the exposure of data collection personnel to hazardous situations (e.g., the need to provide traffic 

control during portable sensor placement or the placement of data collection sensors in the 

roadway without traffic control).

EQUIPMENT CALIBRATION

The State or provincial highway agency should have a well-documented calibration plan that is 

consistently followed to ensure that the collected data represent the traffic traveling over the test 

site. As long as a documented calibration plan is followed, portable and permanent equipment 

data will be accepted.

In addition to calibrating the equipment, the highway agency should monitor the equipment 

output to determine if or when an additional calibration is needed. If the equipment fails or 

experiences calibration drift, the agency should plan to repair the equipment within 1 mo. Data 

should not be submitted for times during which the equipment is not properly calibrated.

Forms and procedures for completing the required LTPP Traffic Sheet 16, Data Collection 

Equipment Calibration, are detailed in the LTPP Traffic Data Collection and Processing Guide, 

Version 1.3 (Ostrom 2012).
28

TRAFFIC DATA TYPES AND COLLECTION FREQUENCY

The monitored traffic data submitted to LTPP must consist of the following: volume counts, 

volume counts by vehicle class, truck weights, and ancillary information that supports the data. 

Continuous data collection for classification and weight data from permanent WIM equipment is 

preferred at the WMA test site for two very important reasons. First, it will provide accurate 

traffic loading measurements that are required to develop mechanistic and mechanistic/empirical 

design models. Second, it will provide the base data necessary to better understand the intricacies 

of the interactions among pavement, traffic load, and environment. However, if the State or 

provincial highway agency is unable to collect continuous classification and weight data, 

potential project locations nominated to the SPS-10 experiment will be considered based on the 

amount and type of traffic data available. At a minimum, 2 w of continuous classification data 

4 times per year (a total of 8 w of classification data) should be collected. The highway agency is 

responsible for making sure collected data are representative and account for seasonal variation, 

weekday/weekend differences, and inconsistent truck loading patterns that may occur throughout 

the year. 

TRAFFIC DATA SUBMITTAL

Traffic data collected at the WMA test site must be reported and submitted to LTPP in the format 

defined in the latest version of the FHWA Traffic Monitoring Guide (FHWA 2016). All 

monitored data and ancillary information may be submitted electronically to LTPP. It is 

preferred for the data to be submitted by the agency monthly; however, the data will be accepted 

if submitted quarterly.

The agency must identify each file using the file naming convention in place for current LTPP 

data. Examples are C530200.C1N or W530200.C1N. The following describes the characters 

used in this file naming convention:

• The first character represents whether the file contains weight (W) or classification (C) 

data.

• The second and third characters represent the State/province code (53).

• The fourth through seventh characters represent the site identification number (0200).

• The first character of the extension represents the month of count (C = January).

• The second character of the extension represents the day of count (1 = first day of the 

month). 

• The third character of the extension represents the year of count (N = 2013). 

This filename will allow LTPP to enter the data, store and retrieve the data, and provide a data 

tracking mechanism.
29

The highway agency should keep the submitted data for at least 10 yr, and in no circumstances 

should traffic data be discarded by an agency before LTPP confirms that the data were 

successfully loaded.

SHEET 10: TRAFFIC VOLUME AND LOAD ESTIMATE UPDATE—NO SITE COUNT

If a WMA test site does not have weight data, the agency must submit an LTPP Traffic Sheet 10. 

A Sheet 10 records the AADT and ESAL estimates for test sections during the monitoring period 

when no other site-specific or site-related traffic volume classification count and weight data 

were collected or classification data but no weight data were collected. For the WMA test site, 

submitting one Sheet 10 per year is sufficient. Forms and procedures for Sheet 10: Traffic 

Volume and Load Estimate Update – No Site Count are detailed in the LTPP Traffic Data 

Collection and Processing Guide, Version 1.3 (Ostrom 2012). 

31

REFERENCES

AASHTO. 1993. AASHTO Guide for Design of Pavement Structures, 1993. Washington, DC: 

American Association of State Highway and Transportation Officials.

AASHTO. 2020. Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, 3rd 

Edition. Washington, DC: American Association of State Highway and Transportation 

Officials.

ASTM. 2020. Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys. 

ASTM D6433. West Conshohocken, PA: ASTM International.

FHWA. 2016. Traffic Monitoring Guide. Washington, DC: Federal Highway Administration.

Ostrom, B. 2012. LTPP Traffic Data Collection and Processing Guide, Version 1.3. Report No. 

FHWA-HRT-09-051. Washington, DC: Federal Highway Administration.

Puccinelli, J., P. Schmalzer, K. Senn, and L. McDonald. 2022. Long-Term Pavement 

Performance Warm Mix Asphalt Study Final Report, Volume II: SPS-10 Experimental 

Matrix and Research Plan. Report No. FHWA-HRT-22-019. Washington, DC: Federal 

Highway Administration.

Walker, D. 2012. LTPP Directive TDP-36, Issuance of LTPP Field Operations Guide for SPS 

WIM Sites, Version 1.0. Washington, DC: Federal Highway Administration.

HRDI-30/02-23(WEB)E Recycled

Recyclable

Recommended citation: Federal Highway Administration, Long-Term Pavement 

Performance Warm-Mix Asphalt Study Final Report, Volume III: SPS-10 Nomination 

Guidelines (Washington, DC: 2023) https://doi.org/10.21949/1521717