In Routific, you can lock certain drivers' routes to prevent them from being changed as you're planning by clicking the 🔒beside a driver's name in the timeline.
You can lock/unlock individual routes, or all routes.
What Changes Can't I Make to a Locked Route?
When you lock routes:
you cannot drag and drop stops into locked routes
you cannot edit stops or drivers belonging to locked routes
you cannot lock or unlock routes in Live mode
when re-optimizing, locked routes will not be affected
when inserting unscheduled stops, locked routes will not be affected (see GIF below)
Note that you can continue to make changes on unlocked routes.
Example
Here's an example of how you can leverage the power of locking routes.
Let's say you have 20 optimized routes, and you are satisfied with 17 of those routes. You can lock all routes, then unlock the three routes you'd like to change.
Click "Reoptimize" and let the algorithm reshuffle the three unlocked routes. You can rest assured the 17 locked routes you are happy will stay untouched!