I came back from Manchester on Saturday afternoon when conditions were very bad. Dark , gloomy, heavy rain, spray. Why is it that so many car drivers drive on side lights or none at all in these conditions. Dont they realise they are practicaly invisible in our mirrors in heavy rain. Apart from the fact that i always thought in was illegal to drive on side lights. Do the police do anything. No. It doesn’t make any money for them does it. Also whats this new rule that you can exit a motorway with no indicator signal and just give one flash of an indicator when you are already in the slip road. Thats if you remember where the switch is. 
Some of them will certainly not realise they are invisible to us in spray, there will be idiots as well though. I wonder if them in the blue-grey, silver or metallic light green type colours know just how invisible they are!
Like a lot of things, there should be educational programmes on the telly to let em know, it aint rocket science is it, if stuff is on the telly millions see it.
tortoise:
Apart from the fact that i always thought in was illegal to drive on side lights.
Not if there is street lighting it’s not 
Mal:
Some of them will certainly not realise they are invisible to us in spray
This was something I was rather surprised to learn on my Class 2 course - how ineffective side lights are on high-speed roads in wet weather.
Yeah, things over the years have got better spay wise. It wernt so long ago that there wernt such a thing as spray suppression, Im sure theres more than a few on here remember the amount of spray the early triaxles would pump out in heavy rain, and we wernt limited either!