To my mind the problem will exist forever as with three large retail developments (ASDA, Mostyn Champneys and Parc Llandudno) within such a short distance of each other, and such developments being in the centre of the Town, it was destined to be a problem from day one.
A partial solution could be possible by a major redesign of the roads around that area and creating total one way traffic, essentially making one huge roundabout of Mostyn Broadway, Conwy Road etc.
ZXZ