Camino Portugues Trail Classification System
After a couple hundred miles of walking on the Camino Portugues I have come up with a trail classification system. Brierly talks some about it, but my system is more specific, with 5 classes. 
Category 1 Woodland Tracks or Boardwalks. Great walking- only bicycles, foot traffic or tractors. If you get run over by a tractor you have a death wish. Cyclists only warn you sometimes; it is best to look before you change sides of the trail. Much of the way is delightful.
Category 2: It’s a beautiful day and I want to smell the flowers. Narrow roads and limited sight distance but less traffic and it isn’t fast. Includes industrial areas and 4-lane roads with good sidewalks. Not nerve- wracking but listening for vehicles approaching from behind is important. A quiet street can get crowded in a few seconds; be ready to step into a driveway or doorway.
Category 3: Ends your Camino prematurely if your focus lapses. Busy city streets, crossings required, busses, trucks, cars, taxis. Keep alert for traffic lights. “Is that driver really going to stop for me in this crosswalk?” Often comes after Category 1 Trail lulls you into complacency. Watch what the locals do and mind your P’s and Q’s.
Category 4: Pilgrim Highway of Near Death Experiences. No striping, steady stream of cars, narrow shoulders, in first photo cobblestone. Everyone is driving like they are late to work. First photo is deceiving- a rare quiet moment on this country road in southern Portugal, plenty scary the rest of the time. Just wide enough for one car at a time unless the shoulder (where you are) is used. Watch footing carefully, not a time to stumble. Be prepared to jump into the ditch.
Category 5: Pilgrim Highway of Death. Very little shoulder, no escape route (fence, parked trucks, steep bank), steady stream of 80,000 pound trucks at 60 mph just five feet away. Oncoming drivers seen talking on cell phones. The only Category 5 we experienced was just south of Azinhaga, this photo is not of that road (this road and shoulder are much wider and the distance to travel on it short). Takes a significant mental toll on you.
Take a bus or a taxi.
Bohm Caminho
robertcdeming 
Noted!!!
Robert, Love your eating system! What a hoot! I would be interested in your thoughts about stretches of CF with a #4 or 5 rating.
I meant to refer to your “rating” system above–not “eating” system.
Found few of these problems on CF. Much of the area has very few people and the established trails generally safe. Not so in Portugal, this is relatively new.