This version of 2015 FARS file was compiled on 5/18/2016. 
These are the annual FARS release files.
Starting from 2015 file release, there will be two folders, one for national and one for Puerto Rico. 
In each folder, there are three zip files for three different formats. The formats are SAS, DBF and CSV.
In the next couple of years, the support for DBF format will be discontinued.
Starting from 2014, Pedestrian and Bicyclist file is included in the file release.
Auxiliary files are included in the SAS, DBF and CSV sets instead of as independent zip files.
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FARS Auxiliary Files
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The FARS Auxiliary files are datasets that are derived from the standard FARS datasets: 
1. Accident -> Acc_Aux
2. Vehicle -> Veh_Aux
3. Person -> Per_Aux
These files are joined by the standard key variables.
Please read the following document for additional details: http://www-nrd.nhtsa.dot.gov/Pubs/811364.pdf
For User Manuals, please go to: ftp://ftp.nhtsa.dot.gov/FARS/FARS-Doc/FARS_Auxiliary_Analytical_User_Manuals.zip
For SAS Format Catalog, please go to: ftp://ftp.nhtsa.dot.gov/FARS/Auxiliary_FARS_Files_Formats