Enroute Separation
A buddy of mine got asked an interesting question during a check flight. They were in the cruise at FL340 with traffic ahead of them on the same airway and 2000 feet above. The checker asked him if they had adequate separation to request a climb to the same level. My facetious response would likely have been "let's ask and find out!"
It got me thinking though. What separation do ATC use when allocating cruising levels on airways? Also, what separation do they use when granting climb/descent through a level occupied by same direction traffic on the same route?
I've done some research and can find figures for oceanic routes using RNAV 10 and RNP 4 airways (50 or 80 nm and 30 nm respectively). But what about routes under radar coverage? If someone could point me in the right direction that would be appreciated.