Wearing solid blocks of colour is better than, say, team kit or other clothing with patterns on. The whole trick of camouflage, and the whole reason it works, is that it breaks up recognisable shapes. This is exactly what team kit does, and in the wrong circumstances someone wearing patterned clothing may well be invisible to the car driver behind, no matter how brightly coloured their clothing. This is why I like the roadworker's tabard, at risk of repeating myself: because the two horizontal stripes around the waist and one over each shoulder maintains the shape of the human body and is instantly recognisable to drivers. And if I'm not wearing hi viz, I wear a plain red or blue top.