I found
the text of the Virginia law and it says you should move over "if reasonable" and only if you can do it safely, and if you can't move over, you should "proceed with due caution and maintain a safe speed for highway conditions."
The words "proceed" and "maintain" are not legally defined, as far as I know, but to me they don't mean slow down. They mean continue at the same speed.
It's interesting to me, because the penalty is higher than most other states. (1 year in jail and $2500) but the wording is very weak. Almost as if their intention was to raise awareness without actually convicting anyone.