Road condition is fine, except a 2 hour patch at KKH around Chilas, where there is old bouncy road. Also, if you're going via Kashmir, instead of Abbottabad, remember that a long patch on hills before Kohala is uncarpeted where they've put fresh bajri.
As for car hitting, generally it's NO but no one can say for sure, because mostly it's the small landslides from time to time which cause the road to become uneven at specific points. For example I saw a specific spot after Lulusar lake where I heard every oncoming car hitting (Corolla, City, Civic) due to road becoming very uneven after landslide damage.