Of course you need to be well lit and have reflective clothing, and are prepared for the cold. You also need to be more vigilant, and I find it's best to avoid the local nightlife areas, in case of drunks/taxi drivers in F1-mode etc...
Cycling in the dark is much safer, so long as you're well lit up.
I think it comes from drivers not being sure where you start and finish exactly, so to be sure, they give you more room than they would otherwise.
Absolutly love night riding ! Did a good run tonight after work to my Mums which is 18 miles from my work doorstep to her house to get my haircut believe it or not ! Set off back just after 7.15 joined the Trans Pennine just after Timperley,got buzzed by a bat,nearly squished a rabbit all in the dark with my lovely niteriders keeping me company.Left at the Lyme/Warburton junction and carried on up to Tyldesley for what was a very nice ride.Also helped two students trying to get back to Manchester my showing them the way to Glazebrook station on a folder and MTB who were lost in the darkness,if you are on here i hope you got home safely !