The Illinois Supreme Court gave its OK on Tuesday for reporters to use cameras and audio recording devices in Cook County (Chicago) in certain circumstances, a major signal of progress in the state’s nearly 3-year-old experiment with media coverage at trials.

While nearly half of 102 Illinois counties are already participating in the pilot program —launched in 2012— Cook County becomes by far the largest, with more than 400 county judges overseeing more than a million cases a year in Chicago and more than 120 suburbs.

Illinois Supreme Court Chief Justice Rita Garman said in a statement Tuesday she expects logistical issues because of the large media market and volume of cases in the judicial district but that Cook County will “rise to the challenge.”

Another justice, Anne Burke, said she hopes the project leads to less reliance on Hollywood explanations of how law works.

“It’s good for the entire legal system as a means of increasing transparency, educating the public and informing citizens as to how our system actually works as opposed to sensationalized snippets […] on TV series and in the movies,” she said in the same statement.

The Cook County program will officially start Jan. 5 at the Leighton Criminal Court Building in Chicago, where many of the highest-profile criminal cases in Illinois have been tried.

Tuesday’s decision doesn’t mean cameras will become ubiquitous in Cook County courtrooms.

Media are likely to ask for the expanded access for a relatively small number of high-profile trials.

Judges will also have discretion about whether to grant access ? a decision that’s not appealable. And juvenile, divorce and other types of cases stay off limits to cameras and audio.

Then-Chief Justice Thomas Kilbride launched the initiative with the aim of possibly ending camera bans for good someday. And while the program is described as a test, Garman said after taking over from Kilbride last year she didn’t see Illinois ever returning to a blanket prohibition.

The state has allowed cameras to be present during Illinois Supreme Court and appellate court hearings since 1983. But at the time, the ban at state-court trials was continued out of concern that cameras would be disruptive and undermine a defendant’s right to a fair trial.