A speed alarm is triggered when a device is calculated to be moving at a speed that breaches the client set rules on the Grid. By default, all devices added to the Grid have a minimum speed rule of -10 KPH and maximum speed of 100000 KPH, meaning that a speed alarm can not be triggered by accident. This can be edited from the Device menu, please see here for an article on how to edit a device.
Speed alarms appear on the Grid as a blue alert, please see below for an example. The device icon will remain blue until the alarm is acknowledged and reset successfully.