As most children with disability these days go to normal schools?

Here in the States, I assume that most kids with disabilities attend public schools that may or may not have a specialized program for their needs. I am not a hundred percent sure, but I think the IEP is a reason parents have the option to decided where to send their kids. The IEP ensures which type of support a kid with a disability gets. Instead of going to a deaf school, I attended a oral deaf program at a public school. Until I was 16, I was bused two hours from my home to go to the school. My friends who had different disabilities (deaf, autism, Downs', ADHD) also attended public schools with specialized programs. The ones with the most severe disabilities went to high school half of the day while the other half they attended career / self-help classes. Vocational rehabilitation services are / were there as well.

usually they go to the special education rooms in the public school or go to an alternative school

In my town there's a special school that serves as an enrichment program for the disabled children during the summer (I worked there as an assistant one summer) but during the school year they use it as a detention center/school for "bad" kids. The type of children who skip school and have criminal records.