This CD pack contains many traffic noises specially recorded and put into a format to help to reduce a dog's traffic sensitivity. The CD comes with a comprehensive manual to help to explain things.
The reason the CD can be beneficial for dogs with traffic noise fear is that it allows the dog to deal with just the noise aspect of the problem. Once they can cope with the noise, then it will be easier for them to deal with the actual moving traffic.
Further help may be needed to help to train your dog to cope with traffic. The CD simply allows for faster progress by allowing you to present the noise trigger at controlled volumes on a more regular basis, than having to take your dog out several times a day to work at a distance from traffic.