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:
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. This web page contains the database that resulted from this work. The database is current to 2009 - at which point project resources were shifted to compiling and presenting the available information.
You can download the zipped Access format database, by clicking Master LTPP Literature Database.
Similar to the LTPP database, this "Literature Database" was designed to store information per the criteria identified in the project specifications. Being in MS Access, there are capabilities that can easily be incorporated regarding queries and report template creation, but these have not been done to date. At this point, there is an entry form and the underlying table containing all information. The fields in this table are as follows (please note that all of the fields may not apply to every entry):
Contribution: One of five methods of contribution (multiple methods can apply):
Present Benefit: The benefit(s) realized to date.
As presently constituted, when one title applies to multiple benefit categories, it is listed once for each category. That was done for simplicity in generating listings by benefit category.
For the ease of users, a series of PDF files were generated from the database to summarize the results into broad pavement engineering topics.
You can click on the links below to download these PDF files.top
2010 Comparison Testing of LTPP Profilers - Final Report
This report provides detailed information on the 2010 Comparison Testing of LTPP Profilers (otherwise known as the "Profiler Rodeo"). The purpose of the profiler comparison was to: (1) evaluate the static accuracy of the height sensors in the profilers, (2) evaluate the results from the bounce test, (3) evaluate the accuracy of the DMI, (4) compare IRI values obtained by the profilers with those obtained from two reference devices (Dipstick and SurPRO), (5) compare the IRI values between the profilers, (6) compare the profiles obtained by the profilers, and (7) evaluate the repeatability and accuracy cross correlation values for each profiler.
In addition to the report, a CD containing the report and data for nine of the previous LTPP profile rodeos is available through LTPP Customer Support Services (email: email@example.com) or 202-493-3035.
Other LTPP reports regarding profiler comparisons can be found 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.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 Products Online .
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
User Reference Guides
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, 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 223 pages long, and nearly 1.8 MB in size.
A second guide for the Ancillary Information Management System (AIMS) was added in 2012. This document discusses additional materials such as film, distress maps, ERD files, time histories and other data stored by LTPP outside of the database. This information is available to users on request to LTPP Customer Support Services (email: firstname.lastname@example.org) or 202-493-3035. The guide is available here for download in PDF format. It is 48 pages long, and about 500KB 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_SDR27.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