Tolls on the Pennsylvania Turnpike will increase by 6 percent at the beginning of 2019, Pennsylvania Turnpike Commission officials reported Tuesday.

The increase, approved by the commission Tuesday, will go into effect Jan. 6. The most common toll for E-ZPass customers will rise from $1.30 to $1.38, the commission reported, and from $2.10 to $2.25 for drivers paying cash.

The additional revenue will go toward maintenance of the state's 552-mile turnpike system and cover a mandated obligation that the commission provide $450 million to PennDot each year for transit funding. Tolls have increased every year since 2009, in part to pay for a long-term turnpike reconstruction project and to handle debt service.

Tolls also will rise on the westbound Delaware River Bridge in Bucks County, which has not seen an increase since 2016.

The Turnpike Commission's annual payment to PennDot is set to drop in 2022 to $50 million, which could create funding problems for transit agencies like SEPTA that rely on state money. SEPTA is participating in two studies with the Port Authority of Allegheny County at a combined cost of more than $900,000 that will explore ways transit agencies can compensate for the anticipated loss of turnpike money, The Pittsburgh Post-Gazette reported last week.

SEPTA's $750 million capital budget relies on $375 million from the state. SEPTA estimated a third to half of that money can be sourced to the turnpike.

The trend of consistently raising tolls isn't sustainable, said Eugene DePasquale, Pennsylvania's auditor general, in a statement released Tuesday.

"I currently have teams auditing both PennDOT and the Turnpike Commission," DePasquale said. "The results of those two audits could help provide some relief for motorists who are already tired of the toll increases."

DePasquale has in past audits noted the amount of money left uncollected from toll violators, something his office said the Turnpike Commission has become more rigorous about addressing.

The Turnpike Commission raised about $1.2 million in net toll revenue in the previous fiscal year. About 84 percent of the commission's $552 million capital budget goes toward highway projects. Debt service for fiscal year 2019 is projected to be about $670 million.