lessen mistakes with a one-way sign

Twice in the past few years an Ode Street Tribune reporter has seen a car exit from the Rosslyn Safeway parking lot with a left turn onto Wilson Blvd.  That's going the wrong way on a one-way street.  Fortunately Wilson is wide, but the situation nonetheless could create a bad accident.  Adding a one-way sign on the pole across the street would help lessen the frequency of wrong-way mistakes.  A white arrow on the road right in front of the exit would be even better.