If a Stop is only available under certain circumstances, it can still be included in GTFS with some special considerations.
Should I Include Flag Stops and On Demand Stops in GTFS?
Yes! The more robust the GTFS, the more likely a rider is to learn about a service opportunity they did not know was available to them. Flag Stops and On Demand Stops can be included in GTFS without creating confusion on the rider's end and without creating headaches on the agency's end.
Making a Stop a Flag Stop or On Demand Stop
The way GTFS communicates that a Stop is a Flag Stop or On Demand Stop is found in Timed Patterns. This is where a Stop, when included in a Stop Pattern, can have its pickup and drop off values modified to include Communicate With Driver or Call Ahead for Pickup or Drop off.
As such, a Flag Stop or On Demand Stop must be included in a Route's Stop Pattern in order for it to appear in search results for riders.
In some circumstances, there is no defined "Stop;" rather, it may be a town or service area that is available to riders who call ahead and request pickup. In order for a rider to be directed toward this service using apps like Google Maps, a Stop must be included at an approximate location.
Example: Riders along Newcomb Blvd are able to call for pickup on the Blue Route. The dispatcher will tell the driver where to pick up the rider along Newcomb Blvd, which may be a private residence, commercial location, or intersection. The GTFS shows the "Stop" at the end of Newcomb Blvd so that when a rider searches for transit options from Newcomb Blvd, the Blue Route shows up as an option. While the itinerary will show riders should walk to the end of Newcomb Blvd, it will also show that a rider must first call the agency, at which point the dispatcher can inform the rider that they may be picked up at a different location than the "Stop" they saw on an application.
Appearing in Search Results
Because GTFS relies on Stops to determine if a transit option is available to a rider, the frequency and geographic coverage of Stops increases the likelihood of a rider being made aware of Flag Stops and On Demand Stops near them.
Example: A city circulator Route will pick up riders at any intersection downtown. While the website only shows landmarks and major intersections, the GTFS includes stops every two blocks so that a rider is not directed to walk much further than they would otherwise need to. Additionally, if there are other transit agencies that cover this area, the likelihood of your transit agency showing up as an option increases with the density of Stops because many apps will direct riders to the nearest Stop and/or quickest route to their destination.
If a Stop is only a Flag Stop, including the text "FLAG STOP" in the name of the Stop can help alert riders to the nature of the Stop. Because Stop pickup and drop off values are linked to Timed Patterns, if a Stop operates as both a regular Stop and a Flag Stop, a single Stop can perform both functions and should not be named this way.