The “Find Sections” filtering feature in LTPP InfoPave gives users the option to select sections based on experiment type, state/province, etc. This filtering is available in various features of InfoPave where data can be selected at the section level. While using those features, you will be able to apply the “Experiment Type” to define the GPS or SPS experiment and “Location” filters to select the required State/Province.
If you are trying to determine the experiment type of a specific section, you can select the “Section Summary Report” under Data and the experiment number is available in the general information header of the report.
The unique identifier for LTPP section consists of a combination of STATE_CODE (2 characters)-SHRP_ID (4 characters) (e.g., 27-0501). The naming convention for SHRP_ID varies based on the experiment type as discussed below:
SPS sections SHRP_ID:
The SPS sections have two SHRP_ID systems; the first system is applicable for SPS-1 to SPS-9 projects and the second system is applicable from SPS-10 going forward.
Construction Number (CONSTRUCTION_NO) is an event number used to relate changes in pavement structure with other time dependent data elements. CN= 1 when a test section is initially accepted into LTPP and is incremented with each change in the layer structure.
For each maintenance and rehabilitation treatment applied to a test section after the start of monitoring under the LTPP program, the CONSTRUCTION_NO (CN) is incremented in the EXPERIMENT_SECTION table. The codes in the CN_CHANGE_REASON field indicate what type of activity was performed to cause the change in CN (For example, a CN_CHANGE_REASON of 19 represents the application of an asphalt concrete overlay). Please see MAINT_WORK codes for the complete code list of CN_CHANGE_REASON. The field CN_ASSIGN_DATE provides a date when the CN event occurred.
As all the table, field, and code information is provided along with the downloaded data, it is no longer necessary for the user to search for this data individually.
If the user is interested in getting the table, field, and codes for all tables in PPDB, it is recommended to download the LTPPTD, LTPPDD, and CODES tables that provide this information using the ‘SQL Export’ feature or using ‘SDR Export’ feature in InfoPave.
In Data Selection and Download, Pavement Structure and Construction select Original Surface construction dates. In any other data export option use the following:
For GPS sections, the INV_AGE.CONSTRUCTION_DATE and INV_AGE.TRAFFIC_OPEN_DATE fields should have the data if state agencies provided the information.
For SPS sections, the SPS_ID.DATE_COMPLETE and SPS_ID.DATE_OPEN_TRAFFIC fields should contain the data if state agencies provided the information.
No. The LTPP Pavement Performance Data Base (PPDB) has different levels of data quality (from A through E, where level E data is the highest quality that has passed all the checks). This is indicated by the field “Record Status” in each table. The Ancillary Information Management System (AIMS) data is stored based on the guidelines but do not have this quality check associated with it.
The recent LTPP data analysis project conducted backcalculation of pavement structural parameters based on all of the falling weight deflectometer (FWD) deflection data collected until 2012. These backcalculated data can be accessed through the Data Selection and Download, SQL Export, and Table Export features.
Please note that some of these data may be absent because some States or Provinces did not provide complete records of maintenance and rehabilitation histories. Any available information can be found under Maintenance and Rehabilitation (M&R) in the “Pavement Structure and Construction” class in the “Data Selection and Download” feature. In order to make sure you are looking at the complete list of tables, check the “Show Advanced Data Classification” option.
The LAB_CODE field is a four-digit character field to help users identify where the laboratory is located and who performed the test. Using the STATE_CODE definition, the first two characters represent the State in which the laboratory is located. The third character indicates what laboratory performed the test (a coded value with details in the CODES table) and the fourth character represents the sample’s test number and is sequentially numbered from 1-9, then A-Z.
The "Climate" class of the "Data Selection and Download" feature lists all the climate tables/fields that have available climatic information. In order to make sure you are looking at the complete list of climate tables, check the "Show Advanced Data Classification" option. You may also choose to narrow down your sections using "Find Sections" before selecting the data to get your desired data set.
Using the “Data Selection and Download” feature under Data, under the "Performance" class, check the “Show Advanced Data Classification” option. The Friction table will be under Surface Characteristics. If you click on “Add to Selection” option, you will be able to preview the data or you can select “Add to Data Bucket” option to download the data.
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