There's one more thing riders should think about when it comes to using the Chicago Transit Authority's new Ventra system.
According to the Chicago Tribune, the ID cards for Chicago Environmental Protection Agency workers are triggering the Ventra card readers, allowing for free entry.
The federal ID cards are used by the employees to gain entry at work, and according to the newspaper's tests, worked about 1 in every 10 swipes on the Ventra card readers.
EPA officials have warned employees not to misuse the cards on public transportation, and a spokewoman says the agency is working with the CTA to fix the problem.
A CTA spokesman said fixing the issue is a simple process and should be completed by end of day Monday.
The new Ventra card system has been beset by problems ever since it was implemented last summer.
Last week, NBC 5 Investigates revealed that some riders were enjoying free rides, swiping cards with no money in their accounts, or even negative balances.