While i think i agree with the message this is conveying I just wasn't quite sure it's placement on the motorway was targeting the correct audience at the most opportune of moments.
Though to be honest I'm not completely sure what it is it is saying. Is it saying I should pick up my litter because other people pick up my litter? Thats not really conveying a good message as it would imply that it doesn't really matter whether I do it or not as someone else will always come along and clean up after me. Or is it saying that I should pick up my litter because other people pick up their own? This is a better message but is promoting a 'sheep' mentality that just because everyone else is doing it we should do it too, which I venomously appose. Why should I do something just because everyone else does it?
Surely a much better message would be 'pick up your litter, it's the right thing to do?' or is that to preachy for today's British citizens? Also whoever is placing these signs should consider their target audience, I personally don't see many litteres on the motorway. Maybe it would be better to stick to the more conventional 'speed kills' as it seems a little more relevent.