WASHINGTON, DC – JULY 12: A taxi whizzes past in downtown on July, 12, 2012 in Washington, DC. (Photo by Bill O’Leary/The Washington Post)

D.C.’s cab drivers appear to be complying with new regulations that require them to take credit cards, city officials concluded following an undercover operation to test whether drivers were obeying new rules.

Three months after all of D.C. taxi drivers were required to install credit card readers in their cabs, the D.C. taxi commission’s  “secret riders” took 91 trips starting and ending in all eight wards and found only six instances where drivers told passengers that their readers weren’t working. In three other cases drivers initially refused to take a credit card, but eventually allowed passengers to pay with plastic.

The operation was conducted over a two-week period and is one of several that will be conducted as the commission works to ensure that drivers are following the rules. According to statistics released this week, 6,693 of the District’s taxis have installed an approved credit card system. (Note: according to the commission, there are 6,500 active cabs but the total number of registered vehicles is over 7,100). Drivers were required to have the readers installed by Oct. 1, 2013.

The undercover operation found other violations including eight instances where drivers refused to pick up a passenger, 12 infractions for providing an improper receipt, 14 infractions for an improper or nonfunctioning credit card device and 22 infractions for not displaying an ID card.

Drivers cited must meet with commission staff and face fines ranging from $100 to $1,000 for each infraction. Commission officials said future undercover operations could focus on drivers that bypass certain passengers — an issue that predominantly affects  African American men.

Also this month, the commission announced it would allow drivers with vehicles from the 1997 model year and older to seek waivers from new rules designed to phase out older cabs. If the cabs are in good working order, pass a 150-point inspection and meet other conditions, drivers can delay having to replace their vehicles for up to three years. Under the original plan, models from 1997 or older were required to be replaced by Jan. 1. There is a $50 fee to apply for the waiver.

Commission spokesman Neville Waters said officials opted to offer waivers because they  recognized that some drivers may not have the financial resources to replace their vehicles.

The District’s taxi fleet has undergone a series of changes designed to make cabs more user friendly and competitive with services such as Uber and Lyft. In addition to allowing passengers to pay with credit cards, D.C.’s cabs now feature new dome lights designed to make it easier for customers to know whether a cab is available for service.