OC Transpo says recent failures with Presto card readers aren't being caused by the system itself, but a glitch in how the card readers process information they receive from computers on board buses.

"We made a number of fare changes and route changes at the end of last year and we uploaded a new database," said Pat Scrimgeour, director of transit customer systems and planning at OC Transpo.

Some riders have been contacting the transit authority directly — by phone and social media — to express their frustrations with the malfunctioning card readers.

"Our staff noticed very quickly there were some improvements that needed to be made."

The route changes that sparked the problem came into effect on Christmas Day, while fare changes kicked in on Jan. 1.

Scrimgeour said, as a result, some computers on buses aren't registering the fact that buses are moving along a proper route.

"It's reading the wrong information into the Presto card reader and saying, 'well, because we're not on a bus route yet, let's not collect a fare'," he said.

We're curious. Have you boarded an OC Transpo bus & your Presto card didn't work (not due to lack of funds). Let us know! <a href="https://twitter.com/hashtag/Ottawa?src=hash">#Ottawa</a> <a href="https://twitter.com/hashtag/ottnews?src=hash">#ottnews</a> <a href="https://t.co/cxFYsqLEN6">pic.twitter.com/cxFYsqLEN6</a> —@CBCOttawa

<a href="https://twitter.com/CBCOttawa">@CBCOttawa</a> as a daily OC Transpo User Presto works 20% the time. That's a lot of free rides for people! —@MegKilmour

<a href="https://twitter.com/CBCOttawa">@CBCOttawa</a> Yes I have a pay-per-ride pass and have had card errors 3 times in the past week on different buses at different times. —@ShutUpCoyote

The glitch has been an issue at about 13 locations where buses start their route, but OC Transpo is hoping to fix the problem in the coming days.

In January, as many as 12,000 trips were affected, said Scrimgeour, the equivalent of up to 0.2 per cent of all fares OC Transpo would normally collect that month.

"It's not something that we consider acceptable, so we are working on it. But, it's not something that has a drastic affect," he said.

"If you look at per day, it could be as much as $700 dollars. It's not going to be very much," said Scrimgeour. "We've got a budget to bring in about $200 million dollars in fare revenue this year. And out of $200 million, this may be about $20,000."

<a href="https://twitter.com/CBCOttawa">@CBCOttawa</a> all the time on my ride home! Driver always waves us on. No one's card works. Originating stop for my bus, maybe an issue there? —@Mustang_Sabby