It's because I failed to see or understand the sign at the right (red arrow right side) on the way up the hill. That sign meant that oncoming traffic had the right of way. The big red circle should have been a giveaway--red for STOP. A red arrow on the left means that oncoming traffic has to stop and let you go. Oncoming cars would be expected to pull over or even back up. I had to back up several times. You often see these signs on narrow roads and ones with tight, blind curves (like this one), although I don't recall ever seeing them on the Amalfi Coast road.
Finding a Place to Park
We found lots of legal and free parking all around Italy. Some (especially in a small town's shopping district or the local piazza) allow parking for 20 minutes or one hour. Of course the parking sign is very recognizable--the blue and white P sign (photo on right). They might have arrows directing you toward parking lots or garages (fairly affordable in Italy).
The next photo at the right shows a parking sign with restrictions: The crossed hammers mean the restrictions apply during the Monday - Friday workweek. If you see a Christian cross, that means the restrictions are for public holidays or Sundays. The words "dal 15/03 - al 15/11" mean that the regulations are in effect from March 15th until November 15th (the day comes before the month when Italians write dates.) The "1 ora" means that you can park for one hour (often village centers have time limits). The "Disco Orario" means that when you park, you need to have a Disco Orario placed in your front window with the dial turned to the hour you started parking. You can pick these up at most Bar/Tabacchi for a Euro or two. If you return too late, you might find a ticket waiting when you return home--or six months later.
And if you have a handicapped placard, by all means bring it to Italy. We found that it is accepted pretty much everywhere. Look for handicapped spots when available--they are painted yellow in Italy (photo on right) with some are marked with a sign. Do NOT park in one of these if there is a number stenciled on the ground or printed on the sign--this would be a handicapped spot for a specific local handicapped person.
But also discovered that you can park for free at pay parking spots--parking lots that use parking kiosks--as long as you display your placard. And you can ask to park for free at public pay lots. Take your ticket and have it authorized by an attendant (if any are around). That's one thing Italy (and Europe on the whole) gets right... treating handicapped people with respect and allowing lots of leeway for them. (To be honest, perhaps it is to offset the lack of elevators and escalators, ramps and wheelchair accessible public toilets in the many, many hilltowns which must make handicapped people feel housebound.)
So, if you see a number on the side of a road that looks like a speed limit, it most likely is, even though the sign might look a bit different than in other areas you've traveled through. This one (photo right) is pretty typical for most areas. Be aware of the difference between MPH and KPH. A posted 50 KPH means the limit is around 31 MPH. You'll see this going through local towns (or even slower). On the autostrada you will typically see 90 (55 MPH) or 120 (68 MPH). We set our TomTom (we called him Tommy) GPS to MPH and the rental car's speedometer was set to KPH, a good method to gauge your speed and learn what local speed limits translate to in terms of MPH, along with the feel of your speed on the road.
Step on the gas, drive safely and enjoy the road ahead, that is, until you see the sign that we all recognize...
The STOP sign.
Unless you are Italian, of course... Then you simply ignore it.
Update 3/31/16: One of my Facebook amici offered an amusing way to remember the two basic types of signs in Italy:
"I triangoli sono di pericolo, I rotondi sono di divieto"
The triangles are of danger, the buttocks are of prohibition --Francesco Catalano