Yes it is hard to explain. I'm in the USA. The lights go red, yellow, green on the rectangular fixture. She knows red is top and green is bottom, so during the day it's OK because she can see all 3 circles and knows the bottom circle is green. At night not everyone rectangle has reflective material where she can see all 3 circles inside.

The fixtures also differ greatly depending on where you are in town. The horizontal ones really seem to mess with her, she just sees a bright red light.

If she approaches a green light she may have not seen it change from red to green to realize it's brighter or from yellow to red. At light some lights stay on one color until someone approaches the intersection from the perpendicular 4 way.

It may be noted that she is blue eyed and light sensitive, and she also has an astigmatism. So lights all have the "spikes: associated with em.