BERLIN -- The Maryland Transportation Authority (MTA) is embarking on an environmental impact study for a potential third span over the Chesapeake.

According to the MTA, about 366,000 vehicles crossed over the dual Chesapeake Bay bridges from Friday to Monday during the Memorial Day weekend and the first official weekend of the summer season. According to anecdotal reports, traffic backed up for double-digit miles during peak times last Friday, stalling the flow of weekend traffic to the resort areas and across the Eastern Shore, just as it has done for years.

However, a study is underway to determine the environmental impact of a potential third span across the Chesapeake. The Maryland General Assembly this year approved the study by legislation and directed the MTA to work with allied state agencies on a potential plan to add a third bridge across the bay. The concept certainly isn’t entirely new as previous studies and plans have been conducted in the past, but with the aging Bay Bridges now considered structurally sound but functionally obsolete, the interest in exploring another bay crossing has peaked anew.

The study, which got underway last week, will help determine if and when a new bridge will be needed. What the study won’t do, however, is suggest where a future third crossing should be located. In the past, various suggestions have been made, including another span from Miller’s Island in Baltimore County to a point in Kent County, which would be north of the existing bridge complex, or a southern crossing between Calvert County on the western side and Dorchester County.

State Senators E.J. Pipken, an Eastern Shore Republican, and John Astle, an Annapolis area Democrat, submitted the bill authorizing the transportation authority to conduct and complete the study by Jan. 1, 2014.

The Department of Legislative Services’ fiscal and policy note attached to the bill suggests the new span could cost around $3 billion, or about $700 million per mile, but the study will not consider financial constraints. Pipkin has said the study will only “determine the remaining life of the current spans and determine if and when a new crossing should be constructed and operational.”