Many people with disabilities have service dogs that are specifically trained for their tasks. If a person is blind, the dog is taught to guide them. While there are now many categories of guide dogs, dogs for the blind are still the most common. It takes up to 2 years to train these dogs. They must first be taught how to cope with a wide variety of people in public situations. Their behavior in public must be focused on guiding their person safely. Once this part of their training is complete, they are then taught how to assist a blind person. They learn how to guide people through traffic, busy walk areas and in buildings.