(ThyBlackMan.com) (In light of recent events we are re-printing this vital information. Please share it widely.) If you are pulled over to the side of the road by the police, here is what you should do…
Make no sudden movements. Keep both hands in view on the steering wheel until the officer reaches you. When he asks for your papers, tell him where they are, and ask him if you can get them. If it’s dark, switch on your inside lights before he reaches you so he can see inside and know that you have nothing to hide.
If the police ever say to you “You are under arrest!” here is what you should do. Number one, do not resist the officers in any way. Likewise if you are with a companion who is suddenly taken into custody, say or do nothing about it at 
that point in time. Once he is arrested by the officers, it is strictly out of their hands. The matter has to be settled by the courts. If you want to help him, notify his family.
Later, come to the trial to testify on his behalf, but do nothing at the time and place he is apprehended, even if it appears as though the police are using excessive force. Just observe and come forward and lodge a complaint at the proper time. If you come upon the scene of an arrest, do not join the crowd, particularly if it is becoming unruly.
When being questioned by officers, it is generally advisable to answer them fully, if you are innocent of any crime. However, whether innocent or not, if at any time during questioning, for any reason whatsoever you no longer want to answer, you have the right to remain silent until you see an attorney. You may then be arrested,but you cannot be required to say anything more until a lawyer is present.
When being questioned by officers, it is advisable to treat them courteously. Nothing can be gained by arguing. Even if they are being abusive, at that point the cards are stacked against you. Either answer their questions calmly, or wait until you have a lawyer.
If officers ask to be let into your home, or search the trunk of your car, ask to see their search warrant. If they do not have one, you do not have to let them in. If they insist on entering, do not try to stop them. Let them in, and calmly state that you are doing so against your will.
Closely observe their badge numbers and their names. Do not ask for this information, or be seen writing it down. Also remember their descriptions. You may want to later make a complaint. The police have systems of cataloguing and investigating complaints, but they have proven ineffective, and often counterproductive. You are advised to obtain an attorney in the case of serious abuse.