edit_speed: Adjust Travel Speed in a GTFS Dataset

Description

The `edit_speed` function adjusts the travel speeds between stops in a GTFS dataset by modifying trip durations based on a specified speed multiplier. It allows selective adjustments for specific trips and stops or applies changes globally across the dataset.

Usage

edit_speed(gtfs, trips = "all", stops = "all", factor)

Value

A GTFS object with updated `stop_times` reflecting the adjusted travel durations.

Arguments

gtfs: A GTFS object, preferably of class `wizardgtfs`. If not, the function attempts to convert it using `GTFSwizard::as_wizardgtfs()`.
trips: A character vector specifying the `trip_id`s to modify. Defaults to `"all"` to include all trips.
stops: A character vector specifying the `stop_id`s to include in the adjustment. Defaults to `"all"` to include all stops.
factor: A numeric value representing the multiplier for the speed. For example, a value of `2` doubles the speed, halving the travel time.

Details

The function performs the following steps:

1. Retrieve Durations: The `get_durations()` function calculates trip durations, filtered by the specified trips and stops.
2. Adjust Durations: Durations are divided by the speed factor to compute new durations. Time differences are calculated.
3. Update Stop Times: Cumulative time differences are added to the `arrival_time` and `departure_time` columns in the `stop_times` table.

If no specific trips or stops are provided, the function adjusts all trips and stops in the GTFS object.

Examples

Run this code

edit_speed(for_rail_gtfs,
          trips = for_rail_gtfs$trips$trip_id[1:2],
          stops = for_rail_gtfs$stops$stop_id[1:2],
          factor = 1.5)