The bottom 11km portion is wide and smooth with great switchbacks, averaging around 8%. After Castaldia (1090m), the top 4.6km is a narrow mountain lane through alpine meadows, averaging about 6%, with some steep ramps in the last km or so.
Today was a beautiful August weekend, so lots of cars heading for Piancavallo on the main road. I went by a couple of riders who were also climbing, while dozens of early risers zoomed downhill. But after turning off at Castaldia the mountain lane was mostly deserted. A lady on a trekking bike asked me if the road downhill went to Piancavallo. I told her to take a right at Castaldia. Shortly afterwards her husband rolled by, so hopefully they found their way.
Great descent- very fast and fun. On the ride back home two older guys, tucked-in and clutching their bikes' aerobars, passed me going up hill by Hotel Royal. They were fast!
Edited to add: Later in the afternoon Marilyn wanted to go for a walk, but it was too hot where we live (300m), so we put the dogs in the car and drove up toward Col Alto. We hiked a ways along Viale delle Malghe, a trail which connects numerous hikers' shelters along the mountains' crest. Beautiful wildflowers, karst outcroppings, alpine trees, views of the pianura. And the dogs had a blast.