get_stop_frequency: Get stop frequency

In gtfstools: General Transit Feed Specification (GTFS) Editing and Analysing Tools

Get stop frequency

Description

Returns the number of departures and the mean headway at each specified stop_id within a given time of day, by service_id. Optionally, the departures can also be counted by route_id (and by direction_id, if the field is present in the trips table).

Usage

get_stop_frequency(gtfs, stop_id = NULL, from, to, by_route = FALSE)

Arguments

gtfs	A GTFS object, as created by read_gtfs().
stop_id	A character vector including the stop_ids to have their frequencies calculated. If NULL (the default), the function calculates the frequency of every stop_id in the GTFS.
from	A string. The starting point of the time of day, in the "HH:MM:SS" format.
to	A string. The ending point of the time of day, in the "HH:MM:SS" format. Must be later than from.
by_route	A logical. Whether the departures should be counted by route_id (and by direction_id, if present in the trips table) at each stop. Defaults to FALSE, in which case the departures of every route that serves a stop are pooled together.

Value

A data.table with the columns stop_id, route_id and direction_id (only if by_route is TRUE, the latter only if present in the trips table), service_id, departures (the number of departures from the stop within the time of day, including each departure generated from the frequencies table) and mean_headway (the mean headway within the time of day, in minutes). Stops with no departures within the time of day are not included.

Details

The function counts stop departures: each stop_times entry with a departure time is a departure from its stop, except for the entry of the last stop of each trip (the one with the highest stop_sequence), from which vehicles don't depart. Entries with blank departure times (such as those of stops that are not timepoints) are not counted, so their times should be interpolated beforehand to count them. A stop visited twice by the same trip is counted twice. Its results are therefore not comparable to those of get_route_frequency(), which counts trips.

The stop_times entries of trips listed in the frequencies table are just templates: these trips depart every headway_secs from start_time until (but not including) end_time, and each of these departures visits the template's stops with the times shifted accordingly, as in frequencies_to_stop_times(). Trips without any departure time in stop_times don't generate departures. An error is raised if the frequencies table has invalid entries for the trips that serve the specified stops, even if they don't have any departure time.

The stops are those listed in stop_times, which are never stations. Use get_children_stops() to get the stops of a station and sum their departures.

A departure is counted when it happens at or after from and before to, so that consecutive time windows (e.g. "06:00:00"-"07:00:00" and "07:00:00"-"08:00:00") don't count the same departure twice. Please note that this differs from filter_by_time_of_day(), which keeps entries whose times are equal to to. Departures after midnight are listed with times greater than "24:00:00" and belong to the previous service day, so a time of day such as "24:00:00"-"26:00:00" should be used to account for them.

The mean headway is the length of the time of day divided by the number of departures. It is an average over the whole time of day, so it is larger than the actual headway when service starts or ends within it. Trips with an NA direction_id are grouped together.

Examples

data_path <- system.file("extdata/spo_gtfs.zip", package = "gtfstools")

gtfs <- read_gtfs(data_path)

stop_frequency <- get_stop_frequency(
  gtfs,
  from = "07:00:00",
  to = "09:00:00"
)
head(stop_frequency)

stop_ids <- c("18848", "18960")
stop_frequency <- get_stop_frequency(
  gtfs,
  stop_id = stop_ids,
  from = "07:00:00",
  to = "09:00:00",
  by_route = TRUE
)
stop_frequency

gtfstools documentation built on Oct. 28, 2026, 5:13 p.m.