A Driver is any external or internal condition that motivates the organization to define its goals, and possibly require changes to the way an organization operates. For example, a change in regulation or compliance rules such as the General Data Protection Regulation (GDPR), Sarbanes Oxley, or a competitor feature.
The Driver definition enables you to specify the Goals that the Driver initiates, and the Organizations.that the Driver motivates.
The Driver can be visualized on the Goal/Objective/Service diagram.