Personally it’s crossing the freeway where I live. My city has about 100,000 people but only six roads cross the freeway, with three more wayyy on the outskirts that are basically detours. There are also only a few pedestrian bridges that cross it, and zero pedestrian tunnels. The way our freeway works is it goes around downtown with the ocean to the south and west, so people live on the outside of the freeway and then commute inwards. This means insane bottlenecks with miles of cars in both directions trying to get to the other side. It doesn’t help that our four freeway entrances are also at some of these tunnels / bridges, which means people who need to get on or off the freeway are also present. In general it’s a shitshow and I’d really like to see a few more bypasses to prevent this congestion in the future.
My town has a lot of one-way roads but mostly due to really terrible futureproofing from the 1880s. Back then a lot of streets that they considered “side-streets” were incredibly narrow. Nowadays those are suburban streets that just aren’t wide enough for two cars, so they made them into one-ways.