Introduction

Developed as part of pooled 

fund study TPF-5(013), the LongTerm Pavement Performance 

(LTPP) Performance Forecast 

produces freeze/thaw performance predictions for both rigid 

and flexible pavements. These 

predictions are based on 

regression models using data 

available from approximately 

800 in-service test sections in 

the LTPP database. These 

sections consist of a variety of 

climates with various subgrade 

types and a range of loading 

conditions. Using the LTPP 

Performance Forecast, researchers can compute roughness, 

structural cracking, environmental cracking, rutting, and 

faulting predictions as a function 

of pavement age. The forecasts 

are based on user-defined inputs 

for traffic, structure, environment, and subgrade conditions.

Complete details on the model 

development and the pooled 

fund study can be found in the 

final report, Effects of Multiple 

Freeze Cycles and Deep Frost 

Penetration on Pavement 

Performance and Cost (FHWAHRT-06-121).(1) Because the main 

objective of the study was to 

quantify the impacts of frost 

on pavement performance, the 

models developed and implemented in this application cover 

both frost and nonfrost regions 

and are applicable to a range 

of climates.

Application and Use

The LTPP Performance Forecast 

can be used by State, county, 

and local agencies to forecast or 

estimate performance trends for 

pavement sections of interest 

in specific user-defined environmental settings.

While the LTPP Performance 

Forecast is not a pavement design 

program, it can be used to help 

agencies check and calibrate a 

mechanistic empirical-based 

pavement design program 

(i.e., the Mechanistic Empirical 

Pavement Design Guide (MEPDG))

against local conditions.MEPDG 

was developed using national 

models that represent the average 

performance trends throughout 

the United States. The final corresponding report documented 

significant differences in pavement performance across the 

United States based on various 

environmental conditions. As a 

result, agencies should 

consider calibrating MEPDG for 

their local conditions by adjusting MEPDG calibration factors. 

Procedures on how to use the 

LTPP Performance Forecast to 

calibrate MEPDG models to local 

conditions are described in the 

final report. This is particularly 

useful for agencies that do not 

have measured pavement 

performance data available for 

calibration purposes. Similarly, 

the LTPP Performance Forecast 

could also be used to check and 

develop pavement performance 

trends used in an agency’s pavement management system. The 

online application can be found 

at www.ltpp-products.com.

Example

A screen shot of the international 

roughness index (IRI) prediction 

computed for a flexible pavement 

is provided in figure 1. This prediction was based on pavement 

condition, pavement structure, 

traffic loading, and environmental 

information input by the user. 

The values in parentheses for 

each input provide the user 

with the range of data that was 

used in developing the models. 

Extrapolation outside of these 

ranges should be performed 

with caution.

PRODUCTBRIEF

LTPP Pavement Performance 

Forecast
http://www.fhwa.dot.gov/

pavement/ltpp/index.cfm

Research, Development, and Technology

Turner-Fairbank Highway Research Center

6300 Georgetown Pike . McLean, VA 22101

Visit us on the Web at www.tfhrc.gov

november 2010 FHWA-HRT-10-080

HRDI-30/11-10(1M)E

Figure 1. Flexible pavement example.

Reference— Jackson, N. and Puccinelli, 

J. (2006). Long-Term Pavement 

Performance (LTPP) Data Analysis 

Support: National Pooled Fund Study 

TPF-5(013): Effects of Multiple Freeze 

Cycles and Deep Frost Penetration on 

Pavement Performance and Cost, Report 

No. FHWA-HRT-06-121, Federal Highway 

Administration, Washington, DC.

Researchers—The Contracting Officer’s 

Technical Representative (COTR) was 

Larry Wiser, HRDI-30.

Distribution—This ProductBrief is being 

distributed according to a standard distribution. Direct distribution is being made 

to the Divisions and Resource Center.

Availability—This ProductBrief may 

be obtained from the FHWA Product 

Distribution Center by email to report.

center@dot.gov, fax to (814) 239-2156, 

phone to (814) 239-1160, or online at 

http://www.fhwa.dot.gov/pavement/ltpp/

index.cfm. The software can be obtained 

at ltpp-products.com.

Key Words—LTPP data, Freeze, Thaw, 

Pavement performance, Regression, 

and Models.

Notice—This document is disseminated under the sponsorship of the 

U.S. Department of Transportation in 

the interest of information exchange. 

This document and the report it summarizes present some authors’ opinions 

that may not necessarily be those of the 

Federal Highway Administration. 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 ProductBrief 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.