The New Jersey Turnpike Authority will have to provide evidence to show why it raised its E-ZPass violation fee from $25 to $50, under a ruling by a state appeals court Friday.

The ruling came in a legal challenge filed in 2017 by two motorists who claimed the hiking of the fee roughly six years earlier was unreasonable and in violation of state law.

Plaintiffs James Long and Homer Walker also filed suit in federal court, and that action has been on hold pending the state court's review.

Long and Walker claimed the higher fee wasn't related to the actual cost of enforcement and that the turnpike authority has been using it to generate revenue for its operating fund.

The turnpike authority has countered that even the higher fee doesn't cover the cost of processing and collecting toll violations, which it has estimated at $80.

The three-judge appeals panel ruled Friday that the turnpike authority complied with rulemaking requirements when it raised the fee, but it ordered the two sides to hold an evidentiary hearing in front of a judge in Middlesex County to resolve the matter.

"A full evidentiary hearing is vital to explore the foundation for NJTA's assertion that the $50 fee is a 'reasonable administrative fee considering all of the actual costs associated with the system of collecting tolls from violators,'" the panel wrote. "Such a hearing ideally should encompass expert testimony, cross-examination, and neutral judicial inquiry."

In Friday's opinion, the judges viewed with skepticism the plaintiffs' separate claims for damages or refunds but said that issue could be part of the evidentiary hearing.

Spokesman Thomas Feeney said Friday the turnpike authority was pleased that the judges validated the rulemaking process.