The LTPP program relies on data 

collected by weigh-in-motion 

systems that measure the traffic 

stream

The LTPP program receives and analyzes 

data from weigh-in-motion systems that 

measure traffic streams. For example, weighin-motion measurements collected at one 

location in Arizona found that traffic loads 

were much lower than would be typically 

expected based on their standard design 

tables. By adjusting the pavement design to 

reflect these lower traffic loads, the Arizona 

Department of Transportation was able to 

save more than $2 million and was then 

able to put those savings to work on other 

high-priority highway projects.vi

Long-Term Pavement Performance Program

References

i

ii

iii

iv

vi

vii

v

Long-Term Pavement Performance Program: Accomplishments and Benefits 1989–

2009 (FHWA-HRT-10-071). Federal Highway Administration, McLean, VA, 2010, p. 

20. http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/

ltpp/10071/10071.pdf. Note: This analysis was done in 2007, so additional savings to 

the current date have been accumulated into the $2.5 billion.

NCHRP Synthesis 381: Falling Weight Deflectometer Usage, A Synthesis of Highway 

Practice, National Cooperative Highway Research Program, Transportation Research 

Board, Washington, DC, 2009.

Long-Term Pavement Performance Program: Accomplishments and Benefits 1989–

2009 (FHWA-HRT-10-071). Federal Highway Administration, McLean, VA, 2010, 

p. 6. http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/

ltpp/10071/10071.pdf.

Highway Statistics: 1958, U.S. Department of Commerce, Bureau of Public Roads, 

Washington, DC, 1960.

Highway Statistics 2013, Federal Highway Administration, Washington, DC, 2015.

Long-Term Pavement Performance Program: Accomplishments and Benefits 1989–

2009 (FHWA-HRT-10-071). Federal Highway Administration, McLean, VA, 2010, p. 

11. http://www.fhwa.dot.gov/publications/research/infrastructure/pavements/

ltpp/10071/10071.pdf.

LTPP 2014 and Beyond –What is Needed and What Can Be Done? (FHWA-HRT-15-017), 

Federal Highway Administration, McLean, VA, 2015. http://fhwainter.fhwa.dot.gov/

publications/research/infrastructure/pavements/ltpp/15017/15017.pdf.

Publication No. FHWA-HRT-16-013

 HRDI-30/12-15(1.2M)E

Selected Standards and Tools Founded on LTPP Practices

Standard or Tool Application LTPP Contribution

Weigh-in-Motion Collection of reliable traffic loading and 

classification data

Developed standard calibration 

procedures and processes

Highway Performance Monitoring System 

(HPMS) database requirements for ride, 

cracking, faulting, and rutting data

Highway Performance Monitoring System

Developed LTPP definitions for ride, 

cracking, faulting, and rutting data that 

provided the basis for these requirements

ProVal Software Review and processing of pavement profile data 

to monitor and evaluate pavement roughness

Developed prototype software as part of 

an LTPP data analysis project

AASHTO R 32-09 Calibrating the Load 

Cell and Deflection Sensors for FWDs

Ensures that FWD data used in pavement 

structural evaluation are accurate

Developed procedures and calibration 

centers in support of LTPP data collection

Equipment Startup Procedures for 

Resilient Modulus Testing Equipment

Ensures uniformity and accuracy of LTPP 

resilient modulus testing data for bound/

unbound materials

Developed the procedures and processes

Distress Identification Manual for the 

Long-Term Pavement Performance 

Program

Helps to improve and/or standardize surface 

distress data collection Developed the manual

Profile monitoring quality procedures 

and tools

Used to evaluate profiler equipment, compare 

performance of various models against actual 

measurements, and minor data

Developed procedures and tools

LOOKING FORWARD

Continued support of LTPP operations will provide a return on investment between 100:1 and 1000:1 for every dollar spent on pavements in the 

United States. In the report LTPP 2014 and Beyondvii, FHWA has committed to supporting the following activities:

 Maintain the LTPP Information Management System (IMS)

 Continue Monitoring of Existing LTPP Test Sections

 Perform LTPP Data Analysis and Develop Products

 Improve and Enhance LTPP IMS Interface and Functionality

 Implement New LTPP Experiments

 Monitor Control HPMS Test Sections

This commitment is based on the availability of sufficient funding as part of future transportation funding legislation. Continuing the LTPP 

program will yield information of tremendous value to pavement engineers, who will translate that information into strategies 

and procedures for building better, safer, and more cost-effective roads.

More Information

More information on the LTPP program and how its products are being used to improve our 

highway system and ensure our highway dollars are well spent is available at http://www.fhwa.

dot.gov/research/tfhrc/programs/infrastructure/pavements/ltpp/.

Researchers — For information related to this document contact the LTPP Customer Support 

Service Center at tel: 202–493–3035 or email: ltppinfo@dot.gov. 

Distribution — This document is being distributed according to a standard distribution. Direct 

distribution is being made to the Resource Centers and Divisions.

Availability — The document may be obtained from FHWA Product Distribution Center via e-mail 

report.center@dot.gov, tel: 814–239–1160, or fax 814–239–2156, or online at http://www.

fhwa.dot.gov/research.

Key Words — Research, Long-Term Pavement Performance Program, Performance Measures. 

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

Transportation 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 

TechBrief only because they are considered essential to the objective of the document.

Quality Assurance Statement — The Federal Highway Administration 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.

Summary of Key Benefits 1989–2015

The Long-Term Pavement Performance Program

Knowledge Into Action . . . Performance Data for Pavement Innovation
The LTPP data were used to calibrate the Mechanistic-Empirical Pavement 

Design Guide (MEPDG), adopted by the American Association of State Highway 

and Transportation Officials (AASHTO) in 2008 and incorporated into the 

AASHTOWare Pavement ME Design software, as one example of the practical 

use of this unique dataset.

The value and benefits of the LTPP program are also evident in the many new 

tools and procedures that have been developed as a result of the program. 

For instance, the regional falling weight deflectometer (FWD) calibration 

centers that were established for the LTPP program now serve a broader public 

purpose; highway agencies and private firms can bring their FWDs to the centers for calibration testing. Falling weight deflectometers, 

which are towed to a roadway and used to determine the structural properties of the pavement, are faster and less destructive than 

traditional test methods, which involve removing cores from the pavement. However, the FWDs must be periodically recalibrated to 

ensure they are accurately recording a pavement’s response. The costs of an incorrectly calibrated FWD quickly add up; the Indiana 

Department of Transportation determined that an FWD that was only 1 

mil (a thousandth of an inch) out of calibration resulted in additional 

construction and maintenance costs of $17,000 per mile.ii

The LTPP program also developed the Distress Identification Manual 

(DIM), which provides a standardized means of identifying and recording 

cracks, rutting, potholes, and other evidence of pavement distress. The 

DIM is now used by over half of the country’s highway agencies, the 

Federal Highway Administration, and many local highway agencies.

Yet another product, the LTPPBind software package, allows highway 

agencies to select the proper grade of asphalt binder—the “glue” that 

holds an asphalt pavement together and gives it its resiliency—for a 

specific location. The binder selection process should consider the 

extreme high and low temperatures expected at a pavement site, and 

the temperature models developed under the LTPP program make that 

possible. Using the proper binder, as determined by LTPPBind, saves 

highway agencies more than $50 million each year.

iii

The products mentioned here are just a small sample of the advances 

made as a result of the LTPP program. Research conducted for 

the program has generated information, technologies, and 

practices that have improved the way we design and build 

modern-day pavements. Every State and Provincial highway agency in the United States and Canada is a partner in the program, and all 

have benefited from the knowledge gained. The following table shows additional examples of products that are a result of the LTPP program.

 KNOWLEDGE INTO ACTION

Beginning in 1987, highway agencies and researchers have been monitoring, recording, and evaluating the performance of pavement 

sections on roadways in communities across the United States and Canada. Their mission: to learn why some pavements perform better 

than others so that future pavements can be designed and built to last longer. Their response: the Long-Term Pavement Performance program.

To build durable, resilient pavements, the materials that go into the pavement mix and 

the type and thickness of the pavement layers must be carefully selected for the expected 

traffic and weather conditions. Building durable pavements demands knowledge of how 

different pavement materials and mixes respond to varying traffic volumes, traffic loads, and 

environments.

The LTPP program has been collecting this critical data by monitoring how in-service roadway 

pavements perform. The pavement sections are routinely monitored over their service life until 

they reach the point of failure. What researchers learn about when and why they fail 

provides crucial information on how to build better, longer lasting, and more 

cost-effective roadways.

More than 2,500 in-service pavement sections at over 1,000 locations throughout the United 

States and Canada have served, and continue to serve, as the source of LTPP data. The test 

sections were carefully selected to represent an array of conditions and pavement types, and 

new experiments have been developed over the years to address evolving pavement design 

considerations.

The information gained from LTPP data helps researchers to understand which pavement designs perform better than others in 

specific circumstances, and why. Armed with that knowledge, pavement engineers can make well-founded decisions about pavement 

components, construction methods, and maintenance and repair strategies. The result: State, county, and city governments 

can be confident that the pavements constructed in their communities will provide a smoother ride, with fewer 

delays, for many, many years.

PERFORMANCE DATA FOR PAVEMENT INNOVATION — BENEFITS TO DATE

The LTPP program has already accumulated an estimated $2.5 billion in savings for highways.i

 Recognizing that, on average, taxpayers and 

departments of transportation spend over $150 billion per year on highway infrastructure, if observations and findings from this program help to 

increase the typical 20-year pavement design life by 1 year (or 5 percent), that is a savings of over $7 billion annually. Even if pavement design 

life is only increased by one month, that is still over $500 million in savings each year.

To help researchers and practitioners’ access and make sense of the large amount 

of data collected and stored since 1987, the data have been made available 

through the program’s Web-based portal, LTPP InfoPaveTM. More than 8,000 researchers from 120 countries have already accessed the 

LTPP database and are using the data for local and international studies and analyses.

Highway agencies are not the only beneficiaries of the LTPP 

program. Families across the country will benefit, too. The Surface 

Transportation Policy Project estimates that family spending on 

transportation is at least five times greater than that spent by all levels 

of government; this translates to more than $220 billion per year 

from families’ budgets. Even a savings of 1 percent generated by LTPP 

findings would yield tremendous benefits: a $2.2 billion reduction in 

costs to motorists.

By continuing to support LTPP program activities, highway agencies—

and all roadway users—will benefit from annual returns that exceed the 

total investment in the program.

The Long-Term Pavement 

Performance Program

The Long-Term Pavement Performance (LTPP) program started 

in 1987 as part of the Strategic Highway Research Program 

(SHRP), a five-year applied research program funded by 

the 50 States. The LTPP program was established with a 

multidecade horizon, which would allow the test sections to be 

monitored until they reached the point of failure. 

When SHRP ended in 1992, the Federal Highway 

Administration (FHWA) assumed responsibility for continuing 

the LTPP program. All 50 State highway agencies, as well as all 

Canadian Provinces, participate in the program.

Traffic on U.S. highways has changed 

dramatically over the past 50 years

In 1958, when the Nation’s population was half what it is today, 

there were 68 million cars, trucks, and buses on the road. Since 

then, the number of vehicles has grown almost fourfold—to more 

than 253 million—while the total lane-miles of pavement has 

grown by less than 20 percent.iv, v

Take all that traffic and combine it with the age of our highway 

system, and it is no wonder that the Nation’s highways and 

bridges are nearing the end of their service lives. As we continue 

to rebuild wornout pavements, how can we be sure that the new 

pavements will be able to withstand today’s punishing traffic 

volumes and loads? How can we ensure that State and local 

governments, and the taxpayers who fund them, get the best 

return on their investment in highway infrastructure?

The answers to those questions are in the data being collected by 

the LTPP program.

The Long-Term Pavement Performance Program Knowledge Into Action . . . Performance Data for Pavement Innovation