Which form of identification is checked for each flex driver?

The correct answer is the driver's license. This is because the driver's license serves as a comprehensive form of identification that verifies a driver's identity and legal authorization to operate a vehicle. It confirms both the individual’s identity and their driving privileges, which are critical for ensuring safety and compliance in transport operations.

When overseeing flex drivers specifically, it is crucial to check the driver's license to ensure they are legally permitted to drive for work purposes. Additionally, it helps to affirm that they meet any specific requirements, such as age and driving history, that may be mandated by the employer or regulatory authorities.

While other forms of identification can provide information about a person, they do not necessarily confirm the legality of driving in the same way that a driver's license does. For instance, a passport verifies identity and citizenship but does not indicate driving capabilities. An employee ID is useful for employment verification but lacks the necessary driving credentials. Vehicle registration confirms ownership of a vehicle but does not validate the driver's identity or their suitable driving status. Thus, for the context of checking identification for drivers, the driver's license is the most appropriate document.