Actually, the fifth amendment only protects your right not to incriminate yourself. So you may be called upon to testify against your will against some one else (With some limited protections for spouses and such). However, if you were in fact the one driving, you can plead the fifth, and they cannot use that fact against you to prove it was in fact you driving- they have to prove that independently.
(EDIT: I should note that you also have a right to remain silent when questioned by the police- and since they won't know who to charge, there will likely not be a court case to call you to testify at)
> they cannot use that fact against you to prove it was in fact you driving- they have to prove that independently.
5th amendment protections are much weaker for civil cases though.
Part of this judgement was that even though the law labels is as "civil" it looks and acts in fact like a criminal case, and so it doesn't matter what label they put on it, criminal standards apply.