Short Answer
At present, changing a default driver or vehicle on a route can update historical trip data in Trip Preparation (EZDistrict), not just future dates. The system does not yet fully support effective-dated defaults for drivers/vehicles.
Why This Happens
EZRouting stores a single default driver/vehicle for a route/vehicle, not a full history of prior defaults with effective dates.
When the default changes, Trip Preparation reads the current default and applies it across all dates rather than only from “today forward.”
Substitutions/coverage assignments are handled separately and typically remain intact; what changes is the default listed driver/vehicle.
What You Can Do (Until Effective-Dated Defaults Are Available)
Plan driver/vehicle changes carefully
Make default changes at logical cut-over dates (e.g., start of a new term) where historical impact is less critical.
Use Trip Preparation substitutions for short-term changes
For coverage or temporary reassignments, use substitution/coverage tools rather than changing the default driver in EZRouting.
Verify Route Properties
After changing defaults, open Route Properties:
Clear any old driver entries that might be “sticking” in the driver field.
Document operational history externally (if required)
For compliance or auditing, maintain a separate log of which drivers/vehicles ran which routes on which dates until in-product history is enhanced.
Updated