Alec Baldwin ARRESTED In New York City for Illegal Biking

9:30 AM PT -- Alec is going off on Twitter, writing, "Officer Moreno, badge number 23388, arrested me and handcuffed me for going the wrong way on Fifth Ave ... Meanwhile, photographers outside my home ONCE AGAIN terrified my daughter and nearly hit her with a camera. The police did nothing."

And the zinger, "New York City is a mismanaged carnival of stupidity that is desperate for revenue and anxious to criminalize behavior once thought benign."

Alec Baldwin was detained in New York City Tuesday morning after riding his bike the wrong way on Fifth Avenue and 16th street.

Here's the crazy part ... it seems one of the factors in the arrest was that Alec didn't have his ID on him when he was riding.

We're told Alec was taken to the police station so he could be properly identified ... standard ops.

Law enforcement sources tell us Alec was belligerent with officers while in custody ... which resulted in his getting a ticket for disorderly conduct -- on top of the ticket for riding the wrong way.

Sources tell us he was riding alone ... it was just for exercise. Alec's wife was not there.

The ID part of the story is kind of amazing, because Alec is a fixture in New York.