The main purpose of the Monitor Panel is to answer the question "What are the last known locations of my vehicles?".
Vehicles are shown on the map as either Recently Active or At Rest.
Selecting a Recently Active vehicle shows the last one hour of position reports for that vehicle in a 'trail', to visually give a sense of the direction of travel of that vehicle. It also creates a 'tooltip' which gives further information about the vehicle, including who is currently driving that vehicle.
The arrow in the vehicle icon shows the heading of the vehicle as measured by the GPS sensors.
Several map styles can be selected including Street, Terrain, and Satellite imagery.