There's a difference between expungement and acquittal. If GW specifically exempts only expunged records, you'll hafta submit addenda. (If you're wildly loathe to do so, you can call GW and see what kind of permission you can get...)
Massive invasion of privacy though it seemed, I recall several schools requesting to know about *expunged* records when I applied.
Edited to add: I know many law students who submitted addenda for issues much more egregious than repeated traffic violations. Misdemeanors and other crimes didn't prevent them from getting into their top choice schools.