Why do arteries get clogged up and not the veins?

Atherosclerosis is a process that occurs in areas of high shear stress. The plaques tend to form as a result of injury to the blood vessel linings, influx of fatty materials, and then clearance of that material by macrophages which are a cell type involved in cleaning up messes in the body. The fat laden macrophages are eventually encased in a fibrotic plaque where the muscular layer of the artery appears to thicken in compensation for the events mentioned above. It's ultimately a complex process that results, in part, from the dragging/shearing force of the high-pressure high-speed blood going by. This is why it's a problem of arteries and not veins. Arteries have lots of shear stress, and veins have almost none. i took this from another site... kudos questioner... you stumped me lol