WASHINGTON—All taxicabs in the District of Columbia will be required to accept credit cards by March 30.

The D.C. Taxicab Commission announced Friday that it will use its regulatory authority to mandate upgrades to the remaining cash-only cabs that serve the city.

Requiring cabs to accept credit cards was a cornerstone of a broad package of taxicab-industry reforms approved last year.

But implementing the new so-called "smart meters" hit a snag because of a flawed contracting process. A panel of administrative law judges ordered the city to cancel its $35 million contract with VeriFone Systems to install the meters.

As a result, the meters will no longer be uniform. The taxicab commission says cab owners can obtain credit card readers from any company that produces them.