Data User's Corner
This area houses a collection of information that was developed for the use of the LTPP operations team, but which may also be helpful to end-users of LTPP data. A good starting place for visitors unfamiliar with LTPP is the LTPP jargon page. Items on this page include the following:
2015 Comparison Testing of LTPP Profilers - Final Report
The report provides detailed information on the 2015 Comparison Testing of LTPP Profilers (otherwise known as the "Profiler Rodeo"). A comparison between the four Ames Engineering profile/texture devices used by the LTPP Regional Support Contractors to collect profile data was performed from June 8 to 11, 2015 at the MnROAD facility in Albertville, Minnesota. This was the first comparison between the four Ames Engineering devices after they went into operation in April, 2013. Profile and texture data were collected at five test sections for this comparison. The purpose of this comparison was to: (1) evaluate the static accuracy of the profile and texture height sensors in the devices, (2) evaluate the results from the bounce test and the texture sensor check, (3) evaluate the accuracy of the Distance Measuring System in the devices, (4) evaluate the profile data collected by the devices, (5) evaluate the repeatability of IRI values and compare IRI values obtained by the devices with IRI from a reference device, (6) evaluate the repeatability and accuracy of profile data collected by the devices using the cross-correlation method, and (7) evaluate the texture data collected by the devices. The analysis of the collected data showed that all four devices were collecting repeatable and accurate profile data, and that all four devices were collecting similar texture data.
Other LTPP Profiler Comparison Information:
Final Report LTPP Profiler Comparison - 2013 provides detailed information on the 2013 comparison testing of LTPP Profilers.
A CD containing the report and data for eleven of the previous LTPP profile rodeos is available through LTPP Customer Support Services (email: email@example.com) or 202-493-3035.
On the FHWA Turner-Fairbank Highway Research LTPP site at these hyperlinks.
FHWA-HRT-06-064: TechBrief: Quantification of Smoothness Index Differences Related to LTPP Equipment Type
FHWA-HRT-05-054: Quantification of Smoothness Index Differences Related to Long-Term Pavement Performance Equipment Typetop
LTPP Manual for Profile Measurements and Processing
The LTPP Manual for Profile Measurements and Processing details inertial profilometer, dipstick and rod and level survey methodology at LTPP test sections, as well as field and office data handling. This document is for the AMES profilers. It replaces the prior document for the ICC profilers.top
Rigid Pavement Design Spreadsheet
The Rigid Pavement Design Software was developed as a Microsoft Excel spreadsheet to automate the design and analysis procedures for improved guidelines for portland cement concrete pavements as published in the 1998 Supplement to the AASHTO Guide for Design of Pavement Structures, Part II, - Rigid Pavement Design & Rigid Pavement Joint Design. The spreadsheet was developed to make it easier for highway managers and engineers to implement the improved guidelines, which were developed under NCHRP research and validated with LTPP data. The spreadsheet has been converted to a web-enabled application at LTPP Infopave TM. Login to the site and select the Tools tile. Login may be done via social media in lieu of registering with the site.
More information on this product is available on the LTPP Section of the FHWA Research and Technology website.top
LTPP Guide to Asphalt Temperature Prediction and Correction
The use of Falling Weight Deflectometers (FWDs) to provide input to pavement structural designs and rehabilitations has become common, and is expected to increase with the implementation of the Mechanistic-Empirical Design Guide for New and Rehabilitated Pavement Structures (MEPDG).
Because the deflection response of asphalt layers in a pavement structure to loads is strongly influenced by temperature, methods to calculate representative pavement temperatures and temperature correction factors are critical. This guide presents such methods developed using LTPP data.top
IMS User Guide
Everything you wanted to know about the LTPP Database, but were afraid to ask. This guide provides an in-depth look at the contents of the LTPP database, the supporting information in the Ancillary Information Management System (AIMS), the tables behind the LTPP Traffic Analyis application (LTAS), and productive ways to extract information from it. The structure of the database is discussed on a macro, middling and a micro scale. Helpful hints are imparted along the way, and a brief SQL tutorial is included in an appendix. The guide is available here for download in PDF format. It is 269 pages long, and approximately 2.6 MB in size.top
Table Navigator Online
Table Navigator is an online schema for the LTPP database.
This is an off-line version of Table Navigator designed for stand-alone use on Windows computers only. Download the "Table_Navigator_SDR30.zip" file to a temporary directory, unzip it, and run the ".msi" file.top
Directives are documents issued by the organization in control of LTPP (currently the FHWA LTPP team) which transmit directions to the various LTPP contractors. Some of them are for purely administrative purposes, such as those that deal with software upgrades. Others, such as those that deal with data collection practices, may be of great interest to analysts and others collecting similar data. Most of these Directives are converted from the original electronic files, except for some (primarily from the early days of LTPP) for which the electronic files could not be found. In these cases, the documents were scanned and the resulting files are significantly larger than the converted documents. Formatting details such as fonts and pagination may be inconsistent with the printed documents, and therefore these files should be used for reference purposes only.top
LTPP Literature Database
As part of the LTPP Benefit Study conducted by Nichols Consulting Engineers, a detailed search was made on the national and state levels to identify publications or other sources of information describing how LTPP data is being used. The database is current to 2009 - at which point project resources were shifted to compiling and presenting the available information. The most recent version of this information is on LTPP InfoPave under the Analysis tab as LTPP Literature References.top