Isn't it the Contraflow on the A27 at Crossbush which means people are trying to use the A259? If not, then the pinchpoints are doing their usual magnificent work of reducing traffic flow through the village.
When I came home from work this evening the traffic went from the roundabout by the Angmering School right back to the village hall! I've never seen it that bad in the evening before. I'm assuming it's all due to the Crossbush roadworks, and people using the village to avoid it!
As long as the By-Pass (That is for ever) ends in a roundabout at the A259 junction the problem will not be solved. Putting in two lanes on the A259 will mean more and faster traffic, further hampering the escape from the By-Pass. It's the enforced wait at that junction that prompts drivers to cut through the village, even in normal circumstances.