The shuttle would be integrated into the Cumberland Sweep, a planned three-mile multi-use path through the district. Formerly known as the Cumberland Multi-Modal Path, the CID rebranded the project as the Sweep last year. Once complete, the Sweep is expected to connect The Battery Atlanta, Truist Park, Cumberland Mall, the Chattahoochee River National Recreation Area and other local trails.
The Sweep, which would include pedestrian and bike trails, has been billed as Cumberland's version of the Atlanta Beltline. The idea of including an autonomous shuttle led the CID to commission a study from Jacobs Engineering Group, which last month wrapped up the first phase of the three-part study and presented findings to the CID's board.
Similar shuttles have been developed and implemented elsewhere. Jacobs' Xuenwen Le said the vehicles use sensors and light-detecting cameras to sense other vehicles, pedestrians and cyclists. The shuttle would be completely self-driving, but only operate within certain parameters — for example, it would run on a predefined route.
An important point to consider, Le said, is that the technology for autonomous vehicles is constantly evolving.
Looking at existing autonomous shuttles, the vehicles are typically 12-16 feet long, 4-7 feet wide and 6-10 feet tall, Le said. They typically weigh between 5,000 and 8,000 pounds, drive between 10 and 15 mph, and hold between five and 15 passengers.
Typical battery capacity for the shuttles ranges from 5-15 hours, Le said. The shuttles can usually operate at a maximum grade of 12-20%, and can drive in light rain and temperatures of 20-110 degrees.
The shuttles are typically fare-free, and sometimes include an attendant who rides on board.
A key element Jacobs will examine in future phases of the study is ridership estimation. Jacobs' Geoff Warr said they are working to determine "mode shift" — the likelihood that a person will use the shuttle instead of driving or walking, and what factors go into that decision.
Things that may affect ridership include the shuttle's speed, how much time it saves people, demand in different areas of the CID, the cost of parking, and severity of traffic congestion.
Warr added that state Department of Transportation data is being used to determine how many people travel within the CID, and how many people travel to and from it.
The Sweep's shuttle would have its own travel lane. As part of the study's first phase, Jacobs has already evaluated challenges and risks of putting the shuttles on the routes where the Sweep is planned to go. Those include challenges in widening roads and bridges to add a new lane, as well as high grades that the shuttles may not be able to handle.
In some cases, that may involve altering existing lanes or sidewalks to create the shuttle lane, whereas in other cases, the roadway may be widened to build a shuttle lane.
In future phases, Jacobs will be looking at solutions, such as different shuttle routes.
For example, Clark pointed to segment A of the Sweep, which would run on Interstate North Parkway before crossing Interstate 285 to run on Cumberland Boulevard.
"Right as it crosses the interstate, we know that there's a lot going on there ... And so when we're looking to build the infrastructure and activate the (autonomous vehicle), that's going to be a critical point, and to have a lot of conversations if that is a feasible route," Clark said.
As part of the study, CID officials visited a business park in Peachtree Corners in Gwinnett County where an autonomous shuttle operates. The shuttle runs on a 3-mile loop on public roads, with a special lane reserved for the shuttle.
Connie Engel, the board's vice chairwoman, asked if the shuttle in Peachtree Corners was well-used.
Le said that use has been limited due to the shuttle's location in an office park, but that the city hopes to extend it to its town center.
"It's really been treated a little bit more like a pilot," said Kim Menefee, the CID's executive director.
That's also the case at the campus of the Delaware Department of Transportation, where CID officials have conducted a virtual visit to learn about a shuttle there.
The Delaware shuttle, which runs on a 22-minute loop, is mainly being used to research autonomous shuttle technology, Le said. It is slated to be expanded to the nearby campus of the University of Delaware.
"It's important, I think, for us to think about, is that technology is advancing so quickly," Menefee said. "So both the size and scope of the vehicles, but also the speed, that by the time we get to this point, we want to plan for it. And that's what we're doing, is doing all of our work to study and plan. ... By the time we get to implementation, we do expect a more advanced model."
The estimated cost of purchasing shuttles and building the infrastructure needed was not discussed at the meeting.
Clark added that there is "lots of support at the federal level" for electrification and autonomous vehicles. The study, which will be wrapped up next spring, should provide the CID with a road map for implementation, so that it is well-positioned when funding opportunities emerge.
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