A new street “grid” or a dual roundabout are the two new design options for the Mount Vernon Highway/Johnson Ferry Road intersection that the city of Sandy Springs will unveil for public comment at two meetings on March 8.
City officials clearly favored the “grid” – which eliminates the intersection and makes the roads parallel – at a presentation at the City Council retreat in January, citing it as the least expensive and most traffic-efficient option. But it also would require taking several commercial properties and, apparently, running a new cut-through street on the grounds of the Sandy Springs Branch Library.
The city meetings are scheduled for Thursday, March 8, with the first running 10 a.m. to noon and the second running 6 to 8 p.m., both at Congregation B’nai Torah, 700 Mount Vernon Highway. The meetings will be in an open-house format, meaning there will be no presentation, but city officials and hired consultants will answer questions.
The current intersection is an unusual X-shaped configuration complicated by Boylston Drive entering from the south. Located just a block east of busy Roswell Road, the intersection is known as dangerous and gridlocked during rush hour, though traffic can be light at most other times.
For several years, the city worked on a redesign involving dual roundabouts. Those options drew immediate criticism after their 2015 unveiling for the land-taking required and for concerns they would make traffic worse and more dangerous. Last year, Mayor Rusty Paul and the City Council called for other design alternatives. Among their considerations was how a new intersection would fit with connecting projects: possible multiuse paths and multi-modal lanes and a triangular park proposed along Roswell Road.
The new alternatives presented at this year’s retreat involved variations on the original dual roundabouts and the new grid concept.
The roundabouts were shifted 50 or 190 feet to the southeast from their original proposed locations, placing them farther away from Mount Vernon Towers, the senior residences where owners strongly objected to the plan. It is unclear which roundabout design will be presented as a formal alternative at the March 8 meeting.
The grid is a new concept where the intersection would be eliminated, with Mount Vernon and Johnson Ferry reconfigured as separate streets running parallel, though very close together, through that area. Boylston Drive would end at Mount Vernon in a T intersection. To maintain connection between Mount Vernon and Johnson Ferry, a concept sketch shows a new north-south cut-through street created across the library grounds, adjacent to its east parking lot.
The grid came in two versions, with officials favoring a “reduced” or “compressed” version where the streets are pinched together more closely, requiring less land-taking. However, the design still requires a lot of land-taking: all commercial properties on the south side of Mount Vernon between Roswell and Boylston would be taken, including a Chevron gas station and an Enterprise car rental outlet, officials said.
The grid design allows for a multi-use trail to run between the two streets to Roswell Road, said Steve Tiedemann, the city’s manager of projects funded by a transportation special local option tax, which includes the intersection.
The current triangular area to the west of the intersection, where the city wants to build a park, formerly contained several commercial buildings and still has a retaining wall. That wall would remain in the grid design, which does not involve flattening the steep grade of the site, unlike a roundabout, Tiedemann said.
Tiedemann and other city officials showed a clear preference for the grid on both traffic and cost comparisons. Tiedemann said that traffic wait times during rush hour in the year 2040 are worse with roundabouts than with no change at all. And the reduced grid design’s estimated budget of $24.7 million is lower than the roundabouts, at $28.2 million to $29.8 million. Of the grid design’s total budget, $14 million is land acquisition costs.
The city previously spent about $4.8 million acquiring the Roswell Road triangle land from the previous commercial property owners.
I am no traffic engineer, but this I know for sure. The dual roundabouts at Riverside and I-285 have worked magic. I live at the north end of Riverside, and all trips north, west, South beyond Buckhead or East beyond Roswell Road require me to encounter that intersection. Before the roundabouts, it usually took ten minutes and something twenty or thirty to travers that intersect. Since drivers have gotten used to the dual roundabouts, it never takes more than a minute or two.
Just saying.