Smart Routing can be found in the Scheduler in the Web Portal, when you are viewing the 'Day' view. You would need this feature activated on your account in order to make use of it.
Selecting Map will allow you to view the routes and can also select a specific user in order to figure out what the best route would be for them for that day, and order their jobs to go along that route.
To select what User's routes you want to view, select the map pin symbol beside the User's name in the Scheduler. Their jobs will then appear on the map with the best route between them highlighted.
Note: If jobs are set to be day-long, then they will not sort. They must be set for shorter times so that they can line up alongside one another without overlapping in order to make proper use of the Smart Routing.