[nancyminusone]

>signal lights tell me whether or not I can pass

No they don't, they tell you and other vehicles to stop. You would fail your driving test if you depend only on the traffic lights and don't bother to verify it is safe to pass yourself.

[kqr]

The main function of a traffic signal is the green phase, not the red phase. A traffic signal increases throughput by allowing drivers to ignore crossing traffic.

(If safety/the red phase was the purpose, the intersection would use a roundabout instead.)

[dmoy]

I mean, it depends on where you take your driving test. In a lot of places in the US (especially in some rural areas), you may still pass. In some cases you might not even drive near a stoplight during the test.

[AlexandrB]

If you "know a guy" you can even pass a driving test without ever getting behind the wheel of a car. Road licensing is in complete shambles in the last 10 years. A lot of "workarounds" and corruption.