I have a sloped concrete driveway that has been sealed and "traction crystals" were added to the sealer at application. It is still slippery when wet and in winter it is especially bad w/snow. Is there any type of coating or a machine that can "scratch" the surface to help w/traction?
 Hi!
 Unfortunately, I do not know of any traction coating or machine that can scratch the surface to add traction. A sloped driveway is always challenging in any surface material.
 Sorry I didn't have any helpful information for you. 
 Thanks for your submission.
Nancy