Being a law enforcement officer and an educator, I often get asked the question of when to advise someone of their Miranda Rights. While television and movies always depict law enforcement reciting Miranda Rights to a suspect after an arrest has been made, the reality is that Miranda Rights only have to be read to someone when two conditions are present; the person needs to be in custody and is going to be interrogated.
If law enforcement doesn't have both, then Miranda probably won't apply. This means that law enforcement can speak to an individual without advising that person of their Miranda Rights. An officer is allowed to ask questions about the person's name or date of birth, or actually anything that does not involve the reason they are in custody. However, if the officer is going to ask questions about the crime the person was arrested for, then Miranda Rights need to be read to the person.
What is custody?
To put it bluntly, if you have been handcuffed, transported to a police station or jail facility, and asked questions about your name, address, medical history and criminal history, then escorted to a cell, you're probably in custody. However, you may also be considered in custody if a reasonable person would probably believe that your freedom is restricted in some way, and this would be correct.
"You have to read me my rights"
Police officers don't have to read you your rights if the math formula above is not complete (remember: In custody + questioning = Miranda Rights). So if you are arrested and the officer doesn't ask you questions about the crime, then he or she doesn't need to read you your rights.
"You can't question me"
Actually, a police officer can question you about anything he or she wants to question you about. Now whether the answers will be admitted in court is a different answer, and one which is left up to the district attorney, judge and defense attorney to decide.
Custody could also mean other circumstances such as how many officers are present when questioning a suspect.
What is interrogation? These are directed questions that often imply or direct guilt towards an individual. The key for officers and investigators is to know when they have to advise someone of their rights and when they don't have to because the goal of an investigator is getting a suspect to talk about a crime. However, I always advise officers if there is any doubt about whether or not to advise someone of their rights, it's always better to just advise. This will probably minimize the chance of a statement being lost in pretrial motion(s).