[Cementjungle]

Are you considering the act of pulling you over and asking to see your papers "detaining"?

What's the legal basis for the random DUI checkpoints some places (like Los Angeles) do?

[William Tell]

Cementjungle said: "Are you considering the act of pulling you over and asking to see your papers "detaining"?

Absolutely. Next time it happens to you simply ask the cop whether you are free to go or are under arrest. He will answer that you are not free to go and are being "detained".

Cementjungle said: "What's the legal basis for the random DUI checkpoints some places (like Los Angeles) do?"

There is no Constitutional basis for such stops, but merely some court decisions allowing them.

[Still Thinking]

Are you considering the act of pulling you over and asking to see your papers "detaining"?

Yes. Arrest no; detaining, yes.

What's the legal basis for the random DUI checkpoints some places (like Los Angeles) do?

As far as I can tell, there isn't one. SCOTUS disagrees with me, although I'm sure that doesn't cause them too many sleepless nights.