My son (4.5 years old and recently diagnosed high-functioning ASD) has an obsession with signs. Mostly, road work signs, but some other signs as well. He says he likes them because they provide important information to keep people safe. In any case, I'm not real worried about this obsession other than the fact that it interferes with his social interactions. For example, at school he plays pretty well with other kids in the classroom (where there are no signs available), but when the class goes outside for play time he immediately asks the teacher for the signs stored in the shed and then spends almost all the outside play time moving the signs around without much social interaction with the other kids. I suppose we could ask his teacher not to take out the signs, but we will not always be able to do that. So I'm wondering if there is something that can be done to help him move beyond this obsession. He doesn't have any other obsessions as far as I can tell.