As I was informed by staff today that the speed field in RLCs have no effect on the app behavior at all anymore. Furthermore any effects they did have were a bug. "We recently fixed a bug that was triggering the red light cameras' TTS based on the speed field added there. This behavior shouldn't be based on speed, so I highly suggest you create a suggestion on UserVoice for removing this field."
Therefore i recommend removing the speed field from red light cameras entirely in WME. There is already a separate discussion and work being done on the possibility of having combination speed/red light cams added in the future, this suggestion is for exclusive red light cameras.