Here is a quick DIY of a 4 way road crossing to show how this works.
This is a DIY project. If you are looking for a plug and play product, please be patient, we are developing some. In the meantime, if you are a DIY'er, or just can't wait to try this out, then please keep reading.
Required tools: Soldering Iron
Required skills: Soldering, technical wiring skills
We use WS2812B lights because they are addressable LED's. We serially wire them. This means that if one pixel has a fault, all pixels after it will fault. This is good because it becomes easy to identify where a problem lies.
We wire the arduino to the first lighting strip with 12-14 gauge wire. Our solution requires 3 wires here (we used black, red and blue)
Wiring between the individual lights can be as long or a short as you need them to be. We use a very thin wire to connect them. For our solution, we use only 4 wires (black, red, yellow and green)
We wired our arduino - power and ground, and Data In to pin 3.
Our inelegant DIY solution solders the 4 wires to a t-connector as shown. We ended our wires into a plastic connector to make connecting each individual light/signal easier.
As you can see, our 4 wires connected to 5v, ground, data in and data out. (In this double 3 traffic light, we soldered to data out on the reverse side.
*We take no responsibility for the outcome of this project due to soldering skills, or technical know-how*