Hugh Lessig writes here that one rationale for the in-state only aspect of the abusive driver fees is this: "Virginia drivers would chiefly benefit from road improvements that the fees pay for, not those out-of-state commuters or beach-goers." This Post article describes the first Northern Virginia challenge to the abusive driver fees. This AP article describes the arguments in the Henrico County circuit court case.
There might be a way to make an empirical study of the effects of abusive driving by residents as opposed to non-residents, but if the issue is unclear, normally, the legislative gets to make the call - there is no constitutional requirement that the General Assembly has to operate with laser-like precision in their lawmaking.
Jerry Markon writes here in the Washington Post that the conservative majority on the Fourth Circuit has been frittered away, and that there could soon be a long-lasting Democratic majority on the Court. I think that the attempts to categorize the judges on the Fourth Circuit as liberals and conservatives is somewhat overdone, the liberals are more conservative and the conservatives are more liberal than they get credit (or blame) for being in the press. The WSJblog has this take on the article, ConfirmThem has this long take, and SC Appellate Blog has noticed it as well.
This Style Weekly article on Oliver Hill is maybe the best I've read.