Well, I guess everybody figured out how the state of PA is going to pay for all those toll boths they are going to put on I80! Federal guidlines have been around for decades. Some states opted to use them, some didn't. To get more federal highway funds, some of the states that didn't now are following federal guidlines. Same process goes for smog testing. Some states don't do it, some do.Every now & then, the feds will pressure a state to follow fed guidlines for smog inspections to receive federal money for highway upkeep & construction. Kinda like when the proctologist has BOTH hands on your back during an examination!
