While assigning a driver to a dispatch, you can check the driver's availability in the dropdown list in the Driver & Equipment tab.
Driver’s availability
Driver’s will be marked with one of the following statuses.
Once you assign a driver to a dispatch and check the box to notify the driver by email and text, the driver will be notified with the dispatch details. The driver will now respond to the assigned dispatch, and you will be notified of the driver's status update.