RICO’s DIGEST. How many times, driving in the wee hours of the night, have you seen drivers approaching a red light, slow down and then proceed. Also, seen is many a driver who waits for a green light.
The Ley de Transito (Traffic Act) allows, from 10:00 PM to 5:00 AM, drivers to treat the red light signal as a stop sign.

Let me explain. Imagine it is 3:00 am, and you are in downtown San Jose, on Avenida Segunda, for example, where there is literally a traffic at every intersection from the Hospital San Juan de Dios to the Parque de la Democracia.
If you catch the first green and move at the legal speed limit, most likely you will get every light green. But vary the speed, or the first light is red, you will be stopping at every corner for 30 seconds at each and every red light.
No traffic behind you, ahead of you, or crossing any of the intersections. What do you do?
Remember these words, if it is between 10 pm and 5 am, from Monday to Sunday, carefully approach each intersection and come to a stop (I have to say that for the legality, personally, I prefer a rolling stop) make sure there is no cross traffic, and proceed.
That is the traffic law in Costa Rica.