... is increased rush-hour traffic.
Without traffic, it takes me about 30 minutes to get to and from work. These days, it's taking close to an hour to get home. The increase has been easy to detect and it wasn't until yesterday, when I had plenty of time in the car to think about it, that I figured it out.
Lower unemployment means more people going to work. More people going to work means more traffic.
I wonder if everyone is seeing more traffic these days.