If you’re one of the 72% of Americans taking a road trip this year, don’t forget your toll passes---plural. There are, after all, over 130 toll systems across 34 states, so you better be prepared. Technically, by now, you should be able to have just one transponder. Congress passed a law in 2012 requiring what’s called “interoperability” between all the nation’s toll systems - a concept that means one pass would work for every toll. That law was supposed to take effect in 2016. Yet here you are in 2021, emerging from the pandemic and packing three or four transponders for your cross-country trip. What gives?