Safety in traffic, very important. These lights turn green when you come near the cross-over. The cop standing on the other side of the street won't have much to do. Simple setup. Set the communication channel in the notecard of the cross-over and in the description of the lights themselves. Set the distance from the center of the crossover, and you are good to go. And remember, Safety first !!!! Buy here, or buy in our shop @ hop://grid.avatarlife.com:8002/BST-Corporation/164/143/24 to get an extra discount