cop pulls you over, wants to talk, your freedom to leave has just been lost, try and split. Handcuffs or no handcuffs, your under detention till he says so. From what your saying, he'd have to be Mirandized. In Texas, after he says the majic words, your under arrest, good cops will stay within the law, the 95 percentile will keep asking questions, the people under arrest just keep talking.
Unless you talking about murder cases or cases where it's life w/o parole, etc., the person arrested will sometimes be hollaring the next day "I wasn't read my rights!" to his lawyer. It will go something like this, the lawyer will tell him that he'll make that motion when they go to court, BUT if they go to court, the plea offer that was made previously will disappear and they will be facing ??? years in prison. They usually start to think of what happens when/if they lose, the "did I or didn't I get Mirandized" goes out the window, and he takes the probation or small jail time. That's 99% of the time, that's why you rarely ever here of it, other than TV...