Which document is NOT listed as a valid half-fare card?

The Employee ID is not listed as a valid half-fare card because it typically does not provide eligibility for fare discounts related to age, disability, or specific transit programs. Unlike the other options, the Employee ID generally serves as proof of employment rather than a qualification for a fare reduction.

On the other hand, a Medicare card is recognized as valid for half-fare programs since it signifies eligibility for older adults and can be connected with various transit discounts. The Senior metro card is specifically designed for senior citizens to access reduced fares, and the Disabled metro card is likewise aimed at individuals with disabilities, granting them reduced fares on public transportation. Each of these options is tied to specific qualifications for half-fare privileges, which the Employee ID does not provide.