Apparently, after-dark mail deliveries are becoming so commonplace today that one postal district decided to equip their mail carriers with headband lights so they can deliver after-dark.
According to the article, since the consolidation of postal facilities, all area mail goes to Harrisburg first and then back to areas like Williamsport for delivery, meaning that mail carriers have to start their routes an hour or more later than usual, resulting in after-dark deliveries:
http://www.pennlive.com/midstate/in...ers_get.html