One of the fields that must be specified when creating a new route is the Start Date & Time. This indicates when the driver is expected to begin the route once it is assigned.
Although this may not always match the actual time the driver starts, you can set a default start time for all routes.
For example, if your drivers begin their daily shifts at 8:00 AM, you can go to the following path and enter 8:00 as the default time.
Admin Center -> Settings -> Dispatching -> Routing & Optimization -> Route start time
Now, when you create a new route, this time is already set as the default start time. However, it can still be changed manually in the route creation form.
To learn more about the route ETA and the start time, check here.