I ride this road often as its on the way to my cottage from prague. This road has relatively good visibility and wider lanes compared to many czech roads and this is what makes it one of the better ones.
Definitely stay on high alert, lots of bikers treating it like a race track, and can have a lot of traffic on the weekends.
We ride this route very often as it has plenty of interest for every type of rider. It can become a race track at the weekends and the police do set up road side radar traps.. This route is a favourite for bikers going from Prague to Pokelyn Doly or the Bikers cave pub. Highly recomended. A lot of bikers meet at the Aquip petrol station north of Duba and then scream up to the caves. Do not underestimate the corners as they tighten up and change camber. We have seen many biker accidents due to going to fast on the corners.
This is one of the best rides in the CZ and must be done.