GTFS is designed to evolve to meet new needs. The mobility community shares needs as they arise and suggest ways to add them as extensions to the spec.
Ongoing extension projects
new needs or ideas
your interest in being a producer/consumer of an extension
Everyone is also welcome participate in the discussions at github.com/google/transit/issues.
GTFS amendment process
The process to changing the spec can be found be found here at the links below.