Long-Term Pavement 

Performance Program

LTPP Customer Support and 

LTPP InfoPave 

The LTPP Customer Support Service Center, located at 

FHWA’s Turner-Fairbank Highway Research Center in 

McLean, Virginia, is committed to providing superb and timely 

service with LTPP data requests and other information. Some 

of the services provided by customer support include:

Helping users select the appropriate data for 

their use.

Preparing and disseminating data.

Explaining the structure of the database and the 

	 associated data files.

Explaining the data collection methods and tools.

LTPP data and program information can also be accessed 

directly using the LTPP InfoPave Web site.

LTPP Customer Support Service Center

6300 Georgetown Pike, HRDI-30

McLean, Virginia 22101-2296

(202) 493-3035

ltppinfo@dot.gov

LTPP Web site

http://www.fhwa.dot.gov/research/tfhrc/programs/

infrastructure/pavements/ltpp/

Publication No. FHWA-HRT-15-018

HRDI-30/12-14(1M)E

LTPP Program’s 

Continuing Mission

The LTPP program will yield additional benefits as data are added to

the database and as data analysis efforts—some currently planned 

and some yet to be identified—are completed. Continued monitoring

of the test sections that remain in service is needed to obtain data 

encompassing their full performance period. In addition, key LTPP 

stakeholders recognize the necessity of strategically establishing new 

LTPP experiments. In light of rapid growth in the use of warm-mix 

asphalt, an LTPP Warm-Mix Asphalt Overlay experiment (SPS-10) is 

underway, and the establishment of an LTPP Pavement Preservation 

experiment is under development. Through these efforts, the LTPP 

program will continue to play a critical role in answering the primary 

question, “How and why do pavements perform as they do?” 

General Pavement Studies (GPS)

GPS-1: Asphalt Concrete on Granular Base

GPS-2: Asphalt Concrete on Bound Base

GPS-3: Jointed Plain Concrete Pavement 

GPS-4: Jointed Reinforced Concrete Pavement

GPS-5: Continuously Reinforced Concrete 

Pavement 

GPS-6: Asphalt Concrete Overlay of Asphalt 

Concrete Pavement

GPS-7: Asphalt Concrete Overlay of Portland 

Cement Concrete

GPS-9: Unbonded Portland Cement Concrete 

Overlays on Portland Cement Concrete 

Pavements 

SPS-1: Strategic Study of Structural Factors for 

Flexible Pavements

SPS-2: Strategic Study of Structural Factors for 

Rigid Pavements

of Flexible Pavements

of Rigid Pavements

SPS-5: Rehabilitation of Asphalt Concrete 

Pavements

SPS-6: Rehabilitation of Jointed Portland 

Cement Concrete Pavements

SPS-7: Bonded Portland Cement Concrete 

Overlays on Concrete Pavements

Absence of Heavy Loads

SPS-9: Validation of Strategic Highway 

Mix Design (Superpave) 

SPS-10: Warm-Mix Asphalt Overlay of Asphalt 

Pavements 
LTPP Mission Statement

To increase pavement life by investigation of various designs of 

pavement structures and rehabilitated pavement structures, using 

different materials and under different loads, environments, subgrade 

soil, and maintenance practices. 

What is LTPP? 

Started in 1987 as part of the Strategic Highway Research Program 

(SHRP) and managed by the Federal Highway Administration 

(FHWA) since 1992, the Long-Term Pavement Performance (LTPP) 

program studies the performance of in-service pavements. The 

primary goal of the LTPP program is to understand how and why 

pavements perform as they do. To accomplish this goal, researchers 

collect pavement performance data using standard data collection 

procedures and protocols on a variety of pavement types. This 

information is stored in a database that can be used by pavement 

engineers and researchers worldwide to advance the science of 

pavement engineering.

Since 1989, the LTPP database has grown exponentially and 

includes electronic information collected from 2,509 pavement 

test sections throughout the United States and Canada. The LTPP 

program has two sets of experiments, the General Pavement Studies 

(GPS) and the Specific Pavement Studies (SPS), detailed in table

1. The GPS test sections were established on existing pavements. 

An experimental matrix was used to guide the selection of GPS test 

sections that would cover, to the greatest extent possible, the range 

of factors required to explain pavement performance. Test sections 

for SPS experiments were built to specific designs and thicknesses,

as defined in the experimental plans.

Today, the LTPP program continues to collect performance data for 

over 700 test sections. Approximately 50 percent of the remaining 

test sections are GPS experiments with the majority falling into the 

GPS-6 experiment that evaluates asphalt concrete overlay of 

asphalt concrete pavement. Many GPS-3 experiment sections 

that evaluate jointed plain concrete pavements also remain. The 

remaining 50 percent are SPS experiments. The majority of the test 

sections are in the SPS-2 experiment, which is the study of structural 

factors for rigid pavements, followed by the SPS-8 experiment, which 

is the study of environmental effects on the pavement in the absence 

of heavy loads.

LTPP Program’s Core Functions 

Data Collection and Management, Data 

Analysis, and Product Development

Data Collection and Management

From its inception, the LTPP program has sought to collect data 

believed to be most important in characterizing factors that affect 

pavement performance. The types of data collected are shown in the 

figure. Ensuring consistency and accuracy in

the collection of data are vitally important from 

site-to-site and across States and Provinces. 

Extensive quality assurance processes 

ensure that the database is populated with 

the highest quality data possible (LTPP 

Information Management System Quality 

Control Checks, September 2013). Quality 

control checks include detailed data collection 

protocols; personnel training and certification

requirements applied to ensure consistency in 

data collection and test results; a schedule for 

regular calibration and maintenance of all data 

collection equipment; and a variety of postcollection data checks. 

Collected pavement performance data are 

stored in the LTPP database, which currently 

resides on several high-capacity servers 

and in the Amazon Cloud. As computer 

technology changes, the LTPP database 

also changes so that it remains current with 

technology and accessible to data users. 

The LTPP InfoPaveTM system, which made 

its debut in January 2014, is an interactive 

Web-based system capable of providing users 

with performance and supporting data for LTPP test sections. Users 

of LTPP InfoPave have several new options to access, view, and 

download LTPP data.

Data Analysis

Over the past two decades, data from the LTPP program have proven 

to be useful in advancing pavement engineering technology. The

Strategic Plan for LTPP Data Analysis identifies and prioritizes

projects, tracks projects to completion, and documents future 

research needs. The identified projects are pursued by the LTPP

program as resources permit. LTPP data are also regularly applied 

in research sponsored by individual State highway agencies, 

the Transportation Research Board, and others to address 

pavement performance-related issues. For instance, the SHRP2 

R23 project uses performance data from LTPP test sections to 

focus on pavement renewal alternatives for both flexible and rigid

pavements. LTPP field performance data, in conjunction with other

data sources, are being used to develop products for the SHRP2 

R23 project.

Product Development

Products developed from the LTPP program 

take many forms, including data collection 

guides, test methods, protocols, software, 

and technical guidance. The program’s 

most valuable product is its comprehensive 

database because it is the foundation for 

understanding pavement performance. 

For more than two decades, the value of 

LTPP data has been amply demonstrated. 

For example, the LTPP database served 

as a critical resource in developing the 

American Association of State Highway 

and Transportation Officials (AASHTO)

Mechanistic-Empirical Pavement Design 

Guide (MEPDG), the first new pavement

design procedure in a generation. Data from 

LTPP test sections were used to calibrate 

national default models used in the guide. 

Developers of the MEPDG have said that 

the guide would not be possible if it were 

not for the data and information available on 

a nationwide basis from the LTPP program. 

Other products of the LTPP program include the Distress 

Identification Manual for the Long-Term Pavement Performance 

Program (FHWA-HRT-13-092); AASHTO’s R32-09 procedure, 

Standard Practice for Calibrating the Load Cell and Deflection 

Sensors for a Falling Weight Deflectometer; guidelines for collecting 

reliable traffic loading data; and ProVAL, a software application

used to view and analyze pavement profiles. Additional information

about LTPP products is available in Long-Term Pavement 

Performance Program Highlights: Accomplishments and Benefits 

1989–2009 (FHWA-HRT-10-071). 

Collecting Quality Data

The LTPP program continues to improve its data 

collection and quality control procedures through 

lessons learned and by adapting to changes in 

equipment and pavement technology. Although 

data collection and quality control procedures have 

varied over time, the principal data types collected 

since the beginning of the program, as shown in the 

graphic above, have not. The program has collected these data types in a consistent and systematic 

manner over the years, and they will be the primary 

source for evaluating pavement performance for 

the foreseeable future.