The police are only required to read you your Miranda Rights – that is advising you of your right to remain silent and to have a lawyer – during a “custodial interrogation.”
What we typically think of “being in custody” is not always what the law views as “being in custody.” If you are handcuffed and taken to the police station and told you are under arrest – you are “in custody.” On the other hand, if you are pulled over by police with sirens and lights, while you would feel compelled to stop and not be free to leave, the law does not consider this as “being in custody.” Being “detained” (like a car stop) is not the same as being in custody. Therefore, police are not required to read you your Miranda rights when they pull you over in your car.
What if the police arrest you, take you to jail, but do not ask you any questions? Do the police need to read you your Miranda rights in this situation? No. While you are clearly in custody, you are not being “interrogated,” which means being asked questions designed to get you to incriminate yourself.
HOWEVER, even if police are not legally required to read you your Miranda Rights, you always have the right to remain silent when being questioned about a crime and you should exercise your right to remain silent and consult with an attorney.