It's true, the Camino Portugues has two points to cross "faster than normal", better than say to avoid it. The first is the 9 km you have to walk to leave Porto, and the second one is the Industrial Polygon before arriving Porriño, "As Gandaras".
The ideal for the polygon is to cross it on sunday to avoid the trucks, cars and noises.
Buen Camino,
Javier Martin
Madrid, Spain.