You may have heard the phrase a tired dog is a happy dog. This may or may not be true, but it is true that most dogs need physical activity and social interaction to make good pets. Dog parks are a great venue to provide both of these in a safe, contained environment and have become very popular.
However, with popularity comes use, over-use, and risk. The following site outlines common challenges with dog parks and provides suggestions for those thinking of providing one.
Dog Bites and Liability for Dog Bites by Kenneth M. Phillips