From the ACLU:
To fight police abuse effectively you need to know your rights. There are some things you should do, some things you must do and some things you cannot do. If you are in the middle of a police encounter, you need a handy and quick reference to remind you what your rights and obligations are.
IF YOU HAVE A POLICE ENCOUNTER, YOU CAN PROTECT YOURSELF
IF YOU ARE STOPPED FOR QUESTIONING
IF YOU'RE STOPPED IN YOUR CAR
IF YOU'RE ARRESTED OR TAKEN TO A POLICE STATION
- Be polite and respectful. Never bad-mouth a police officer.
- Stay calm and in control of your words, body language and emotions.
- Don't get into an argument with the police.
- Remember, anything you say or do can be used against you.
- Keep your hands where the police can see them.
- Don't run. Don't touch any police officer.
- Don't resist even if you believe you are innocent.
- Don't complain on the scene or tell the police they're wrong or that you're going to file a complaint.
- Do not make any statements regarding the incident. Ask for a lawyer immediately upon your arrest.
- Remember officers' badge & patrol car numbers.
- Write down everything you remember ASAP.
- Try to find witnesses & their names & phone numbers.
- If you are injured, take photographs of the injuries as soon as possible, but make sure you seek medical attention first.
- If you feel your rights have been violated, file a written complaint with police department's internal affairs division or civilian complaint board.
IF YOU HAVE A POLICE ENCOUNTER, YOU CAN PROTECT YOURSELF
- What you say to the police is always important. What you say can be used against you, and it can give the police an excuse to arrest you, especially if you bad-mouth a police officer.
- You don't have to answer a police officer's questions, but you must show your driver's license and registration when stopped in a car. In other situations, you can't legally be arrested for refusing to identify yourself to a police officer.
- You don't have to consent to any search of yourself, your car or your house. If you DO consent to a search, it can affect your rights later in court. If the police say they have a search warrant, ASK TO SEE IT.
- Do not interfere with, or obstruct the police -- you can be arrested for it.
IF YOU ARE STOPPED FOR QUESTIONING
- It's not a crime to refuse to answer questions, but refusing to answer can make the police suspicious about you. You can't be arrested merely for refusing to identify yourself on the street.
- Police may "pat-down" your clothing if they suspect a concealed weapon. Don't physically resist, but make it clear that you don't consent to any further search.
- Ask if you are under arrest. If you are, you have a right to know why.
- Don't bad-mouth the police officer or run away, even if you believe what is happening is unreasonable. That could lead to your arrest.
IF YOU'RE STOPPED IN YOUR CAR
- Upon request, show them your driver's license, registration, and proof of insurance. In certain cases, your car can be searched without a warrant as long as the police have probable cause. To protect yourself later, you should make it clear that you do not consent to a search. It is not lawful for police to arrest you simply for refusing to consent to a search.
- If you're given a ticket, you should sign it; otherwise you can be arrested. You can always fight the case in court later.
- If you're suspected of drunk driving (DWI) and refuse to take a blood, urine or breath test, your driver's license may be suspended.
IF YOU'RE ARRESTED OR TAKEN TO A POLICE STATION
- You have the right to remain silent and to talk to a lawyer before you talk to the police. Tell the police nothing except your name and address. Don't give any explanations, excuses or stories. You can make your defense later, in court, based on what you and your lawyer decide is best.
- Ask to see a lawyer immediately. If you can't pay for a lawyer, you have a right to a free one, and should ask the police how the lawyer can be contacted. Don't say anything without a lawyer.
- Within a reasonable time after your arrest, or booking, you have the right to make a local phone call: to a lawyer, bail bondsman, a relative or any other person. The police may not listen to the call to the lawyer.
- Sometimes you can be released without bail, or have bail lowered. Have your lawyer ask the judge about this possibility. You must be taken before the judge on the next court day after arrest.
- Do not make any decisions in your case until you have talked with a lawyer.