Highway Numbers
Pennsylvania renumbered all of their highway exits a few years ago. The exit numbers now correspond to mile markers. On long highways like I-79, that makes them a lot more sparse. I can rarely remember the mileage exit numbers, though. I-90 is either near 160 or 180. I-76 is either near 70 or 80. This weekend, I think I noticed funny properties that will make it easier to remember. To go from I-79 to I-76, get off at 77, which is conveniently close to 76. To go from I-79 to I-90, it's almost 180, which is double 90.