A set of electronic signs displaying either a green down arrow or a red letter X indicating whether a travel lane is open or closed. These are generally found on major bridges in the Northeast, where lanes may be adjusted during the respective peak hours to allow for an additional lane in one direction at the expense of the other. Additional uses include commuter based arterial routes, such as U.S. 19 through north Atlanta and U.S. 6 (Dodge Street) through Omaha, Nebraska.