Managing bus detour: Trip Modifications & GTFS

The management of bus detour is a major issue for operators, caused by various factors such as roadworks, accidents or other events. To manage these situations, a sub-specification of the General Transit Feed Specification (GTFS) called GTFS Trip Modifications has been developed.

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GTFS Trip Modifications: a tool for managing detour

GTFS Trip Modifications is a format used to communicate deviation information to operators. Once a detour has been published, the operator and traveler information application is able to :

• Close the unserved segment completely
• Mark stops to indicate that they are not served
• Retrace the new route
• Position temporary stops

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How are detours displayed in the application?

_{<a id="anchor2" class="anchor"></a>Deviation} detection

Deviation detection is based on tracking three consecutive passages on the same line that make the same change. This configuration can be adjusted according to the size of the network and the number of stops.  

Temporary stops

In the case of a detoured segment, if an existing stop on the GTFS - belonging to another line, for example - is present, it will be used for the detour. However, there are cases where a stop is completely new and temporary. In this case, someone has to go out into the field and position a sign indicating a temporary stop. The application is able to differentiate between these two types of stop.

Feedback to operators

The GTFS Trip Modification format is used to return information directly to transport operators. Operators can configure their websites to ingest this raw data, which they can use and publish in their own way.  

They can choose to represent detours differently from the way they are presented in the application.

Continuous vehicle monitoring

The application of a continuous vehicle monitoring module also enables detours to be detected and highlighted on a dashboard. An e-mail alert can be sent to signal the detection of a detour. This action takes place prior to publication in the application.

However, the information is not immediately published for the user, but is passed on to the operator to inform him of the detection of a detour on his system. It can be presented in a dashboard or by e-mail, and modifications can be made before deciding whether or not to publish this information in the GTFS RT feed. In this way, the operator has total control over the management of detour information.

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Conclusion

Detour management, a key factor in service quality, can now be greatly facilitated by GTFS Trip Modifications, a dedicated application and customized data use.