immediately vs straight ahead

immediately

adv
  • In an immediate manner; instantly or without delay. 

conj
  • directly (as soon as), instantly, the moment that. Indicates that the independent clause describes something that occurs immediately after the dependent clause's referent does. 

straight ahead

adv
  • directly ahead, without deviation 

How often have the words immediately and straight ahead occurred in a corpus of books? (source: Google Ngram Viewer )