get_vkt: Get vehicle-kilometres travelled

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

Get vehicle-kilometres travelled

Description

Returns the vehicle-kilometres travelled (VKT) by each specified route_id: the length of each of its trips, counted once for every departure of the trip on every day on which its service runs. VKT can be restricted to some dates and to a time of day.

Usage

get_vkt(gtfs, route_id = NULL, date = NULL, from = NULL, to = NULL)

Arguments

gtfs	A GTFS object, as created by read_gtfs().
route_id	A character vector including the route_ids to have their VKT calculated. If NULL (the default), the function calculates the VKT of every route_id in the GTFS. route_ids not listed in trips are ignored, with a warning.
date	A Date vector (including IDate) or a character vector of dates in the "YYYYMMDD" or "YYYY-MM-DD" formats. If given, only these dates are counted. If NULL (the default), every day on which the services of the routes run is counted.
from, to	Strings in the "HH:MM:SS" format. If given (both must be), only the departures at or after from and at or before to are counted. If NULL (the default), every departure is counted.

Value

A data.table with the columns route_id, n_days (the number of counted days on which at least one counted departure of the route runs), vkt (the vehicle-kilometres travelled on these days, in km) and vkt_daily_mean (vkt divided by n_days, in km per day), sorted by route_id. Routes without any departure on the counted days (and within the time of day) are not included.

Details

The VKT of a route is the sum, over its trips, of the length of each trip times its number of departures times the number of counted days on which its service runs, according to the calendar and calendar_dates tables. Departures are counted as in get_route_frequency(): trips listed in the frequencies table depart once per headway, the other trips depart once, and departures after midnight belong to the previous service day. Unlike in get_route_frequency(), the time of day includes to, as in get_trip_length(). An error is raised if the frequencies table has invalid entries for trips that run on the counted days.

Trip lengths are calculated with get_trip_length(), along the shape of each trip from its first to its last stop, so trips to and from the depot are not included. If the GTFS has no shapes table, the straight-line distances between stops are used instead, with a warning. Trips whose length is unknown (e.g. trips without a usable shape, which also raise a warning, or trips listed in frequencies but not in stop_times) add nothing to the VKT, but the days on which they run still count in n_days. If no counted trip of a route has a known length, its vkt is NA.

See Also

get_vmt() for vehicle-miles, get_route_frequency(), get_trip_length(), get_summary()

Examples

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

# VKT of every route over every day of the feed's calendar
vkt <- get_vkt(gtfs)
head(vkt)

# VKT of two routes in the morning peak of a single day
get_vkt(
  gtfs,
  route_id = c("CPTM L07", "2002-10"),
  date = "2019-03-04",
  from = "07:00:00",
  to = "09:00:00"
)

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