I've been through court quite a few times now so this isn't super new to me... however, i cannot find any case law at all about signs not being visible due to sun set light.
Long story short - I made a U-turn at a controlled intersection with traffic lights (from the left turn lane). I was facing westbound prior to the left turn lane right before sunset. There was one no u-turn sign for the entire intersection and the sun happened to be right beside the sign (as it was setting).
Due to this setting sunlight glare, I could not see the sign.
from O/Reg 615
Because the road is straight with no curves, would the sign be considered not visible?
45. A sign prescribed by this Regulation, other than a sign prescribed by section 13, 14, 15, 24, 25, 26 or 27, shall be so placed as to be visible at all times for a distance of at least 60 metres to the traffic approaching the sign. O. Reg. 175/08, s. 15.
(also, i feel like the reason why backlit signs exist is for this reason)