creating vignettes ... ERROR
Error: --- re-building ‘gtfs2emis_emission_factor.Rmd’ using rmarkdown
Quitting from lines 186-211 [unnamed-chunk-10] (gtfs2emis_emission_factor.Rmd)
Error: Error: processing vignette 'gtfs2emis_emission_factor.Rmd' failed with diagnostics:
no applicable method for 'drop_units' applied to an object of class "c('double', 'numeric')"
CMD check is raising this error: