Is these sentences are relative pronouns?

Hi there.

Example:
1. The book, which I read last night, was exciting.
2. I walked on a street, which happened to have a pile of dog dirt, which I did not see because I was too exhausted.

According to what I understand, a relative pronoun acts as the subject or object of the verb in the relative clause. Example: ''The car, which was a taxi, exploded.''

Thanks in advance.