So it is, from 10 pm to 5 am, drivers cross an intersection even if the light is red. Yes, you read that right, even if the light is red.
However, it doesn’t mean you just ignore the red light. 
The Traffic Law (Ley de Transito) stipulates that between those hours, the red traffic light becomes akin to a stop sign: you need to come to a full stop, check for vehicles and pedestrians crossing and then advance.
The other important note is that it’s not mandatory to advance on red. Even if there are others behind honking their horn.
Now you know.