Long-Term Pavement Performance Ancillary Information Management System (AIMS) Reference Guide

APPENDIX A. AIMS TECHNICAL STORAGE DETAILS

INTRODUCTION

Details on the general formats and directory structure used to store electronic files in AIMS are presented in this appendix. Field names, such as STATE_CODE, from PPDB are used to specify directory folder storage structures. The definitions of these field names can be found in the Long-Term Pavement Performance Information Management System Pavement Performance Database User Reference Guide or the LTPP Table Navigator program distributed with the LTPP SDR and available from the LTPP FHWA Web site.⁽⁷⁾

While some file naming conventions are referenced here, there are cases where a reference is made to other LTPP literature on file naming conventions. Data users interested in using data from LTPP AIMS should contact the LTPP CSSC with questions concerning the contents and formats of these files.

ELECTRONIC AIMS FILE STANDARDS

The following file standards specify required and preferred standards for electronic data files converted from paper, video, and photographic images.

Specifications for Scanned Paper Data Forms

Scanned paper data forms conform to NARA’s Expanding Acceptable Transfer Requirements: Transfer Instructions for Permanent Electronic Records.⁽⁸⁾ References to this standard are also available.⁽⁹⁾

For LTPP purposes, the following minimum specifications were specified:

• Data forms shall be scanned at a minimum resolution of 300 pixels per inch (12 pixels per mm).

• All data forms in a defined category are scanned into PDF files.

• Bitonal (Black and white) scanning is preferred, provided a relatively small electronic file is produced.

• Image compression in the PDF creation process shall use lossless compression methods (JBIG2 Lossless).

The preferred practice is to scan paper data forms formatted primarily in portrait orientation in an up-right orientation when they are opened for viewing.

Specifications for Digitized Video

At the time the original LTPP guidelines were prepared, NARA had not developed national standards for digitized video due to the rapidly evolving nature of digital video formats and the lack of any open, national or international consensus standards for the creation and preservation of digital video. Due to business requirements for smaller file sizes, the following file types and minimum standards are used:

• MPEG1: This is appropriate for older video obtained from Super-VHS video recorders. Minimum frame size is 320 × 240 pixels.

• MPEG2: This is the preferred video compression standard since it is compatible with modern DVD players and is recommended for video collected using digital cameras. Minimum frame size is 320 × 240 pixels. Data rates should not exceed 7 megabits/s.

Other digitized video formats can be used if approved by FHWA.

Still Digital Images

Still digital images obtained from digital cameras or scanned color photographs are stored in JPEG or JPEG file interchange format (also known as JPG).

Minimum standards for JPG files include the following:

• 256 colors.

• Quality compression of 50 or greater.

• 300 pixels per inch (12 pixels per mm).

Images previously submitted to LTPP CSSC not meeting these minimums do not have to be re-imaged unless directed by FHWA.

DETAILS BY DATA/FORMAT TYPE

The following sections provide details on AIMS data, file directory storage structure, and some file naming conventions for some data types. Table 2 presents a summary of the overall file directory storage structure used to store AIMS files on the internal LTPP file servers.

Table 2. LTPP AIMS directory storage structure.

Note: Cal_Type: {REF, REL}, Dis_Type: {MDS, ADS}, Prof_Type : {TPF, PRF, LPF, WSP}, LTAS_Type: {AVC, WIM, VOL}, LTQC_Type: {AVC4, WIM7, DATA}, Data_Type: {INV, MAT\TST, MAT\SAMP, RHB, MNT, FRIC, SPS}, TST_Type: {P07, P46}, and Video_Type: {GEN, DIS, PROF}.

Automatic Weather Station (AWS) Data

AWS data are stored using the following directory structure:

AWS\STATE_CODE\AWS_ID

This directory contains all raw electronic data files downloaded from the AWS instrumentation, EDT files created by the AWSCheck software, and PPDB upload files created by the AWSCheck software. In those cases where multiple EDT files were created by RSCs for an AWS site, a number is appended to the file name extension to make the file name unique. Preferred practice is to assign the appended number starting with 1 for the earliest file and increasing sequentially with time.

For other files, the file naming convention is assigned in accordance with directives existing at the time of data acquisition and/or file creation.

Deflection (DEF)—Falling Weight Deflectometer (FWD) Peak, Time History, and Pavement Temperature Data

The electronic version of the following FWD files is stored in AIMS. The file naming convention is assigned in accordance with directives existing at the time of data acquisition and/or file creation as follows:

• Version 10 “*.FWD” files contain both peak deflection data and time history data.

• Version 20 “*.FWD” files contain both peak deflection data and time history data.

• Version 25 “*.F25” files contain peak deflection data only.

• Version 25 “*.HXT” files are ASCII files containing converted binary encoded time history data.

• FWDWin “*.DDX” files are ASCII files converted from MS Access containing peak and time-history data.

• Highway agency FWD data collected on LTPP sections regardless of format.

In addition, the pavement temperature gradient measurements recorded on paper data forms and performed during FWD measurements are scanned following the guidelines in this document and stored in the AIMS. The following file naming convention is used for these files:

DEF+STATE_CODE+SHRP_ID+SURVEY_DATE (YYYYMMDD).pdf

The following directory/subdirectory structure is used to store both the FWD measurement data and scanned paper pavement temperature gradient data:

DEF\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD)

An example of a directory/subdirectory structure is \DEF\48\480102\20040905.

Deflection Calibration (DEFCAL)—Falling Weight Deflectometer Calibration Files

The following data files are included for DEFCAL FWD calibration files:

• Raw electronic data files generated during a relative calibration test on a FWD used to collect data for the LTPP program. The raw data files should be submitted in the native data collection format with file names in accordance with applicable directives existing at the time of the test.

• Electronic data files produced by the RelCal software containing the results of the relative calibration test results.

• Electronic data files produced by the WinFWDCal software in pavement deflection data exchange format used for calibrations following the AASHTO Recommended Standard of Practice R32-09.⁽¹⁰⁾ This includes FWDCalibrationRecord dd-mm-yyyy.DDX and FWDCalibrationOutput dd-mm-yyyy.DDX. Other electronic files used in this process, such as those produced by the FWD, should also be stored.

• Scanned output showing gain factors from results of a reference calibration test, (certificate of calibration), available Temperature Sensor Check (TSC) forms on a FWD used to collected data for the LTPP program. The files should be named REFCAL_TEST_DATE (YYYYMMDD). pdf.

The following directory structure is used:

• DEFCAL\DEFL_UNIT_ID\4-digit Year\REF – for files associated with reference (annual) calibration. This includes both reference and relative calibration tests.

• DEFCAL\DEFL_UNIT_ID\4-digit Year\REL – for files associated with relative (monthly) calibration.

• Where DEFL_UNIT_ID is the FWD measurement unit identifier used in the MON_DEFL_MASTER table.

Example

DEFCAL\8002-131\1994\REL\DATA Files (e.g., 13020394.RC1 and 13020394.CS1).

Note that this is an example of a file name used during relative calibration. Other file names were used because of the number of attempts made to pass calibration.

DEFCAL\8002-131\1994\REF\DATA Files (SDX1926.GO1, Load188.LO1, and Dyna131A.GO1).

Note that these are example of file names used during reference calibration. Other file name conventions were also used.

Ground Penetrating Radar (GPR)

GPR measurements include the raw data files containing readings every 6 inches (152 mm), a graph of the data contained in the raw data file, a graph of the interpreted dielectric constant versus position, a graph of the interpreted layer thicknesses versus position in the right wheel path and center of the lane, and the upload files used to populate the table in the PPDB that contains the interpreted results.

GPR data are stored using the following directory structure:

GPR\STATE_CODE+SPS_ID\filename.ext.

Pavement Distress Data (DIS)

This data type includes manual distress, transverse profile, automated distress, distress viewer and analyzer (DiVA), and manual distress photo database categories.

Manual Distress Surveys (MDS)

This category includes the manual distress maps (MDM files), manual distress survey photos/images (MDP files), and manual distress data (MDD files). The MDD files include all of the paper data collection forms for a linked manual distress survey data set, which may include the following types of data depending on the type of test section: Manual distress survey summary form (sheets 1, 2, 4, 5, 8, and 9), rut depth measurements (sheet 3), faulting measurements (sheet 6), lane shoulder drop-off separation (sheets 7 and 10), hand drawn distress maps, and transverse profile measurements with the dipstick (sheets DS-7 and DS-8). The file directory storage structure for these data is as follows:

DIS\ MDS\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD).

The appropriate file naming convention for manual distress maps scanned before issuance of directive is assigned in accordance with the relevant LTPP distress directives (e.g., D-17, D-31, D-44, or their successors). File names for digitized manual distress photographs are assigned in accordance with the relevant LTPP distress directives (e.g. D-17, D-31, D-44 or their successors).

Manual distress survey data from sets digitized after issuance of LTPP Directive GO-48 “AIMS Electronic Data Format, Submission Standards, and Dates” contain all paper data forms, including manual distress maps, in a single PDF file named using the following convention:

MDD+STATE_CODE+SHRP_ID+SURVEY_DATE (YYYYMMDD).pdf

For distress data sets where linked distress measurements in a data set were conducted on different days, the first measurement day in the data set is used in the file name.

Manual distress surveys scanned following the old tagged image file format (TIFF) protocol have been replaced by a single PDF file following these guidelines. If changes are made to previously scanned manual distress data causing re-scanning of the data packet, the new data packets are submitted in PDF format.

Examples

DIS\MDS\24\240504\20040609\MDP240504A200401.jpg—Manual distress photograph-1 on section 24_0504 taken on June 9, 2004.

DIS\MDS\24\240504\20040609\MDD24050420040609.pdf—File containing an image of all manual distress data forms from the manual distress survey performed on June 9, 2004 in PDF format.

Automated Photographic Distress Surveys (ADS)

This category includes distress maps interpreted from the automated distress survey images (ADS files) and digitized images from the 1.4-inch (35-mm) photographic distress film (ADP files).

The directory structure for each subcategory is as follows: the file names should be assigned in accordance with the relevant LTPP distress directives (e.g. D-17, D-31, D-44, or their successors).

DIS\ADS\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD).

An example of a directory structure file name is DIS\ADS\24\241006\20010229.

DiVA and Distress Photo Database

The Distress Review Microsoft Access^® file from the DiVA output and the Distress Photo Survey Microsoft Access^® metadata database table is stored in the DIS root directory.

ProQual Transverse Profile (TPF) Data Files

The transverse profile (TPF) archival data file produced by the ProQual software is stored using the following directory structure:

DIS\TPF\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD).

The file name convention produced by ProQual is used for these files.

An example file name is DIS\TPF\01\012106\19921222.

Note that scanned paper data forms containing transverse profile measurements using the dipstick are included in the MDD files defined under manual distress data.

Profile (PRF)—Longitudinal and Weigh-In-Motion (WIM) Sites

Separate folders exist for each profile subcategory—longitudinal profile (LPF) and WIM site profile (WSP). Where applicable, data files created during the archival process using the ProQual software are placed in the corresponding directories in accordance with Directive P-37 or its successor. Specific directions and subdirectory structures for each subcategory follow.

Longitudinal Profile (LPF)

Longitudinal profile measurements that have been collected with both high-speed road profilers and dipsticks are included in AIMS. The following directory structures and subfolders are used:

• PRF\LPF\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD).

  • Example: \LPF\01\012106\19921222

• PRF\LPF\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD)\ERD.

When possible, RSCs have converted raw profiles to the Engineering Research Division (.ERD) format and placed these files in the ERD directory subfolder as follows:

• \LPF\01\012106\19921222\ERD

File names for data from road profilers are assigned in accordance with applicable directives at the time the data were collected.

The following directory structure and file name convention are used for longitudinal profile measurements with a dipstick scanned from the paper data collection forms:

• PRF\LPF\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE (YYYYMMDD)\File_name.

Where:

File_name = PRF+STATE_CODE+SHRP_ID+”_”SURVEY_DATE (YYYYMMDD).pdf.

PRF\LPF\10\101450\20030308\PRF101450_20000308.pdf – longitudinal Dipstick data for section 101450 from 03/08/2000.

WIM Site Profile (WSP)

For the WIM site profile (WSP) subcategory, the following directory structures and subfolders are used for raw data and data in ERD format:

• PRF\WSP\STATE_CODE\SSEELW\SURVEY_DATE (YYYYMMDD)\ filename.ext is used for raw profile data files produced by the field measurement device and named in accordance with the LTPP file naming convention in force at the time of data collection.

• PRF\WSP\STATE_CODE\SSEELW\SURVEY_DATE (YYYYMMDD)\ERD\filename.erd is used for longitudinal profile data converted to ERD format.

Where:

For example, PRF\WSP\36\3608OL \20020913\ERD.

Resilient Modulus Material Tests

This includes electronic test from the P07 test protocol Test Method for Determining the Creep Compliance, Resilient Modulus, and Strength of Asphalt Materials Using the Indirect Tensile Test Device and P46 test protocol Resilient Modulus of Unbound Materials.^(2,3)

The LTPP P07 data is stored using the following directory structure:

MAT\TST\P07\STATE_CODE\STATE_CODE+SHRP_ID\LAYER_NO\ filename.ext.

The LTPP P46 data is stored using the following directory structure:

MAT\TST\P46\STATE_CODE\STATE_CODE+SHRP_ID\LAYER_NO\ filename.ext.

Seasonal Monitoring Program (SMP)

For each SMP site, the following directory structure was created:

SMP\STATE_CODE\STATE_CODE+SHRP_ID\SURVEY_DATE(YYYYMMDD).

This directory contains all raw data files downloaded from the SMP instrumentation and scanned paper data forms collected on the survey date. File names for the scanned paper data forms use the following convention:

File_name=SMP+STATE_CODE+SHRP_ID+”_”+SURVEY_DATE.pdf.

EDT files created by the SMPCheck software and PPDB upload files created by the SMPCheck software are stored in the following upper tier directory structure:

SMP\STATE_CODE\ STATE_CODE+SHRP_ID\ .

In those cases where multiple EDT files were created by RSCs for a SMP site, a number is appended to the file name extension to make the file name unique following the practice for similar AWS EDT files. Uploaded file names are assigned in accordance with the file naming convention produced by the SMPCheck software.

Traffic Data

Traffic data includes electronic traffic data files and scanned paper data forms.

Electronic Traffic Data Files

This category includes all ASCII data files output by the LTQC software, SAS^® software, LTAS, or IRD iANALYZE software. A site may require use of multiple subdirectory structures.

The largest repository of electronic traffic monitoring data contained in AIMS is associated with LTAS data since this software is used by the LTPP program to check and process all traffic monitoring data. Traffic monitoring data collected before implementation of the LTAS software have been processed by this program. The directory structure used to store LTAS data is as follows:

TRF\LTAS\STATE_CODE\STATE_CODE+SHRP_ID\YEAR\data folders by type {AVC, WIM, VOL}.

Examples include the following:

• TRF\LTAS\22\220100\2008\ASCII.

• TRF\LTAS\22\220100\2008\WIM.

The following file storage structures are used for data processed by the legacy LTPP SAS^® and LTQC software. Note that the SAS^® binary data files are being archived and will no longer be generally available since they can no longer be opened.

SAS^® directory structure: TRF\SAS\STATE_CODE\STATE_CODE+SHRP_ID\data folders by type {LEV1\YEAR, LEV2\YEAR, LEV3\YEAR, LEV4\YEAR\WIM7\MONTH, LEV4\YEAR\AVC\MONTH, LEV4\YEAR\DATA, LEV5\INDEX}

For example, TRF\SAS\32\321021\LEV1\1990.

LTQC directory structure: TRF\LTQC\STATE_CODE\STATE_CODE+SHRP_ID\LEV4\DATA\YEAR\data folders by type {AVC4, WIM7, DATA}.

For example, TRF\LTQC\36\364018\LEV4\DATA\1998\AVC4.

IRD monitored traffic data files are stored in a separate directory data structure since they were collected as part of the LTPP SPS Traffic Data Collection pooled fund study and are inputs into the IRD proprietary software which provides additional data review capabilities. This data type is called “per vehicle record” (PVR) and is stored using the following directory structure:

TRF\PVR\STATE_CODE\STATE_CODE+SHRP_ID\data folders by type {BIN, ACSII}.

Scanned Paper Data Forms

For traffic data sheets 1–9, 14, and 15, one PDF file was created containing all of these data sheets with the following name:

File_name = TRF+STATE_CODE+SHRP_ID.pdf.

For traffic data sheets 10, 11, 12, 13, and 16, one PDF file is created containing all of these sheets by the year using the following name:

File_name = TRF+STATE_CODE+SHRP_ID+”_”YEAR (YYYY).pdf.

These files are stored in the following directory structure:

TRF\SHEET\STATE_CODE\STATE_CODE+SHRP_ID\ File_name.pdf.

Other Scanned Paper Data Forms

This data type includes images of digitally scanned paper data forms for non-rejected LTPP test sections. All scanned images of data forms for a particular data type (DT) for a section or project are combined into PDF files. Files with unique file names containing similar data types with other electronic data can be stored in the same low level directory. The following file directory and file naming conventions are used for inventory, material, rehabilitation, maintenance, friction, and SPS. The files are stored in the same structure as other corresponding electronic data with matching DT as specified below.

DT\STATE_CODE\STATE_CODE+SHRP_ID\File_name.pdf

Where DT equals the following:

• INV for inventory data (including global positioning measurements).

• MAT\TST for material test data (one MAT directory with two subdirectories).

• MAT\SAMP for material sampling data (one MAT directory with two subdirectories).

• RHB for rehabilitation data.

• MNT for maintenance data.

• FRIC for friction monitoring data.

• SPS for general SPS project data, SHRP_ID=PROJECT_ID.

For INV, RHB, and MNT data. the following file naming convention is used:

• File_name = DT+STATE_CODE+SHRP_ID.pdf

For SPS data, the following file naming conventions are used:

• File_name = SPS+ “#”+STATE_CODE+SHRP_ID.pdf – for test section specific data

• File_name = SPS+ “#”+STATE_CODE+PROJECT_ID.pdf – for general project data

Where “#” is the SPS experiment number assigned to the project site.

For MAT\TST, the following file naming conventions are used:

• File_name = TST+”_”+L05+”_”+STATE_CODE+SHRP_ID.pdf—For lab data sheets L05, L05A, and L05B. All data sheets for a test section are included in one file.

• File_name = TST+STATE_CODE+SHRP_ID+”_” + Field Set.pdf—For all other lab data sheets. All data sheets for the same field set are stored in the same file.

For MAT\SAMP data forms the following file naming convention is used:

• File_name = TST+STATE_CODE+SHRP_ID+”_” + Field Set.pdf—All data sheets for the same field set are stored in the same file.

For FRIC data, the following file naming convention is used:

• File_name = FRIC+STATE_CODE+SHRP_ID+”_”SURVEY_DATE (YYYYMMDD).pdf.

Examples include the following:

• INV\10\101450\INV101450.pdf—Inventory data for section 10_1450. One PDF file is made for each test section or SPS project.

• SPS\10\100100\SPS100102.pdf—SPS1 construction data for section 10_0102.

• FRIC\48\483855\FRIC483855_19951207.pdf—All friction data for section 48_3855 from 12/7/1995.

• MAT\TST\10\101450\TST_L05_101450.pdf—All lab data sheets L05, L05A, and L05B for section 101450.

• MAT\TST\10\101450\TST101450_1.pdf—Lab data sheets for section 101450, for field set No.1.

• MAT\SAMP\34\340801\SAMP340801_1.pdf—Sampling on section 340801, field set No. 1.

Digitized Test Section Videos (DSV)

This data type includes digitized video of test sections. The digitized videos are stored in the following directory structure:

• DSV\STATE_CODE\STATE_CODE+SHRP_ID\VT\VIDEO_DATE (YYYYMMDD)\file_name.

Where VT equals the following:

• GEN for initial video of test section or other at other dates not included below.

• DIS for video taken during a manual distress survey.

• PROF for video taken through the windshield of a profiler.

For example, DSV\48\481077\GEN\19891202\.

File_Name = VT+STATE_CODE_SHRP_ID+”_”+VIDEO_DATE.fe

Where:

For example, DSV\48\481077\GEN\481077_19891202.mpg.

Digitized Drain Inspection Video (DDV)

This data type contains digitized video from photographic inspections of the subsurface drainage features on SPS-1 and SPS-2 projects. These videos are from cameras inserted into the lateral drains and extended as far up the drain as possible. The digitized videos are stored in the following directory structure:

• DDV\ STATE_CODE \ STATE_CODE + SHRP_ID\ file_name.

Where: