george9219 wrote in
:

They have lights at Martinsville, (they use them for the modified
race), so they could run late.

I don't think they have enough lights to run a televised race, so
if it gets dark they'd probably call it.

If they run one lap past halfway, it's
an official race, and would not be continued.

To be more accurate, if they run one lap past halfway it's an
official race and they do not have to continue it. Whether they
actually do or not is at NASCAR's discretion (altho, since NASCAR
is a slave to the TV folk, the likelyhood of their continuing on
Monday if they're past halfway is pretty much zero).

John