The layer session is not the route session. It should have been given a different name to stop confusion. Driver session = saved from in driver mode and only available to continue to drive the route from where you finished driving. Layer session = a layer you can place assets on that can be handled without effecting the route. Each new layer can be changed without other layers being effected by locking other layers. Session = the saved information like layers, driver commands, industry names and settings. If you edit route that information will not get loaded and you end up with only what you had on the route layer. Edit session and you get all the information loaded.