Download files from NHTSA, unzip, and prepare them.
download_fars(years, dest_raw, dest_prepd, states)Nothing directly to the current environment. Various CSV files are stored either in a temporary directory or dir as specified by the user.
Years to be downloaded, in yyyy (character or numeric formats)
Directory to store raw CSV files
Directory to store prepared CSV files
(Optional) Inherits from get_fars()
Raw files are downloaded from NHTSA.