When you are dealing with something that an animal is afraid of, the best approach is to find his "comfort" distance from the thing that scares him. A busy street makes this a bit more difficult, as you have to find a way to give him that "distance". If you have a car, maybe transporting him to a less busy area might make a good start. Perhaps a side street, where he is comfortably away from busy traffic. You could then walk toward the busy street, pausing as soon as you see some sign of anxiety, and retracing your steps just little until he is in his "comfort zone" again. Gradually…...with the use of bribery and rewards......ask him to approach closer to the scary stuff. Liberally reward him for being there, then retreat. The idea is to not force, let him decide when he is ready. If he feels he can retreat at any time, he will have more confidence. This approach may take awhile, but is less likely to create a permanent aversion. (it works well with spooky horses).