It's easy enough to pop open your phone and check the traffic conditions around you, but if you'd prefer a geekier approach, Weird-Lab uses a Raspberry Pi to display real-time traffic data on a screen.
The build here uses a Raspberry Pi with a touch screen that loads up real time traffic data from any site you want. In this case, it also connects to a Samsung phone for an internet connection so it can work inside a car. The end result is a simple, easy-to-glance-at report of local traffic conditions. Head over to Weird-Lab for the full guide.