Article usage

In sentences two and three, you can say that you went to a library/police station, or that you went to the library/police station. It would depend on what you were trying to convey, and the context in which you said it. However, in sentence one, school can be used with no article, or with either the definite or indefinite article. To go to school (no article) describes an activity, rather than a place. Library and police station do not, either one of them, describe an activity. Going to school (and all that it implies about study and learning) describes an activity, rather than just a place.

EDIT: Here are some examples.

Where ar you going? I'm going to school (activity). What school do you attend? I go to a high school in Morningside Heights (place). I go to the high school on 54th street (place).

Going to e.g. school, university or prison etc (also hospital in UK English) are activities as Setanta says, and can be spoken of without an article:

1.
I went to school - acceptable - omit the article to talk about a period of attending school: I went to school in England; I went to school from 1995 to 2006

I went to a school - acceptable - use the indefinite article 'a' to talk about a school in general terms: I went to a school that was 100 years old; I went to a school where only boys were educated; I went to a school which had a good sporting record.

I went to the school - acceptable - use the definite article 'the' to talk about a particular school: I went to the school next to the park; I went to the school previously attended by Charles Dickens.

2.
I went to library - not acceptable.
I went to a (or the) library: acceptable.
3.
I went to police station - not acceptable
I went to a (or the) police station - acceptable

Thanks for your responses.So, We could omit article if there is an activity (Going to) for Schools, College, University, Prison but not Libraries, museums, Theaters, Hotels, Restaurant, Pubs, Police station. Is there any exception list for (Going to) other than this ?

Could i use article for school in the below case.

There is a school on Oxford street in London.

I have seen many places where articles are being omitted. Is there any general rule / patterns on this.A couple of things which i have seen...

I came here by Car.
I travel by Car.
I came here by Train.
I go to temple/ church every Friday.

Thanks...

I've already provided you with the distinction in the case of school--an activity as opposed to a place. Going to church or temple is an activity, not a reference to a specific place.

By the way, you need the definite article in front of the word "article" in your sentences above. Examples: Can we omit the article? That depends on context--if you are describing a place, you must have the article.

By the way, you are not correct to link this to "going to." The distinction is between a place or an activity. For example: Where have you been? I just came from church (activity). I just came from the new Baptist church on Broadway (place).