Not here to race to the defense of PennDOT, but most people almost never take into account Pennsylvania's topography versus a place like NJ.
PA is one of the Top 5 hilliest/mountainous states in the US; NJ is like Top 15 flattest. It's a very overlooked factor in road maintenance and engineering costs, for sure, not to mention the cost of maintaining and replacing PA's bajillion tiny bridges over it's quadrillion creeks and rivers.
Look at the cost differences back in 2014--I can't imagine what they are just a decade later:
https://www.strongtowns.org/journal/...-actually-cost