Compound is likely the biggest factor regarding traction on smooth pavement.

I used gatorskins as a sort of event tire. Took off the 38 marathons (a plus on the rear) and used 32 gatorskins.

My marathons grip incredibly well; hot, cold, wet, or dry. Much better then the smooth gatorskins, particularly wet.

But then there's always crap on the road I missed the tread.

I've put the marathons back on.