By Tony Romeo

HARRISBURG, Pa. (CBS) – Some state lawmakers are expressing concerns about whether ever-increasing tolls may threaten the viability of the Pennsylvania Turnpike.

Lawmakers held a hearing about a 2007 state law that requires the turnpike to borrow hundreds of millions a year for roads and mass transit. Turnpike officials claim the 50-year plan to run up debt now and pay it down later with annual toll increases is viable.

But, PennDOT Secretary Barry Schoch admitted, “The issue is, could we raise the tolls so much on the turnpike that people will divert and not use it?”

Schoch and other Turnpike officials told lawmakers that their best forecasts give no indication that the turnpike will reach that tipping point, but some lawmakers, like House Democrat William Kortz of Allegheny County, are not convinced.

“The motoring public can’t continue to take on the burden of tolls year after year after… and along with the gas price increase.”

Lawmakers plan more hearings about mounting turnpike debt and the five-year old law that’s driving it.