When you view a vehicle or driver history, the history layer shows the actual behavior of a vehicle. If the vehicle's driver has jobs scheduled during the time period that the history covers, the history layer also shows the scheduled route for handling those jobs as a dotted red line. Jobs where the vehicle actually stopped appear in the history with numbered icons. If there was a problem with the job, the icon includes a small warning symbol.
This lets you compare a vehicle's actual performance with the planned route:
In the previous screenshot, the route the vehicles actually followed to reach their stops are shown as animated red and purple history trails. Jobs along the trails appear as small boxes with numbers. The routes planned for the vehicles, based on their jobs, are shown as static dashed red and purple line. You can see at a glance whether the vehicles took a different route than those scheduled.