Use trread to calculate transit frequencies, and validate transit feeds. trread reads the General Transit Feed Specification into dataframes.
If you need to work with map data consider using tidytransit.
A CRAN version is available:
For the development version from Github:
# install.packages("devtools") devtools::install_github("r-transit/trread")
If you would like to contribute please feel free to issue a pull request or open an issue.