andys280176 wrote:
I do have a red/grey colour deficiency but I can easily tell red from green and have never had any problems before until now. What the problem is is that all the background lights are bright white/yellow and it is very difficult to see the red light in the midst of all this, not the colour just the light.
The thing with a red/green deficiency is it is insiduous. We don't know any different until something happens to demonstrate how serious the problem is. FWIW, I can tell the difference between red and green under normal circumstances. But strange things happen when faced with coloured lights and I sometimes fail to see a red light against a field of background lights, or fail to distinguish green and yellow lights from white.
For most people with a red/green deficiency, the frequency response of the low-frequency colour receptors (commonly called red cones, although the peak response is yellowish orange) respond to a higher frequency range than normal. That means that red is subdued. A red light appears less bright, and so is more likely to merge into a field of lights, which is exactly the situation you describe. A person with normal colour vision would not have the same problem because their eyes are more sensitive to red, and thus a red light would appear brighter and so stand out more against a light field.
That said, with one in eight males in this country (and about one in fifteen of the population overall) having a colour deficiency, it is wrong that the local authorities don't make allowances. AFAICT, not making those allowances may even constitute not making reasonable adaptations under the disability legislation that became law last October.