A $6 billion mass-transit plan remains suspended over Nashville’s congested roadways, but the race to develop self-driving vehicles may also help Music City alleviate its traffic headache.
Over the last few years, transportation has emerged as a top priority in Middle Tennessee, where commute times are expected to lengthen by 114 percent by 2040, according to the Nashville Area Metropolitan Planning Organization’s Regional Transportation Plan.
Nashville Mayor Megan Barry is advocating for a regional mass transit system and is supporting Tennessee Gov. Bill Haslam’s funding plan, which includes a 7-cent gas tax hike and a provision to allow cities to seek voter approval for additional taxes to pay for mass transit, according to the Associated Press.
On the autonomous car front, Nashville was selected in October as one of five cities worldwide to join the Bloomberg Aspen Initiative on Cities and Autonomous Vehicles. The designation provides Nashville additional resources, including access to data and coaching, to help the city become better-equipped for the rise of self-driving cars.
Last week, the U.S. Department of Transportation announced 10 locations nationwide to serve as "automated vehicle proving grounds," although there aren’t any test sites in Tennessee.
Erin Hafkenschiel, Mayor Barry’s director of transportation and sustainability, said it’s too early to tell when autonomous cars can put a dent in the traffic problem.
“Based on the testing that has been done, if there was a very significant turnover in current cars to autonomous cars, like we're talking 85 to 90 percent, at that level they become safer than human-driven cars. We know that level would improve congestion,” she said. “I think what remains to be seen is that when there is a lower penetration of autonomous cars and more of a mix, it's a bit more unclear of how that will improve congestion.”
Hafkenschiel said autonomous cars are not a “silver bullet solution,” but can play a part in an overall transportation strategy, with Nashville’s $6 billion mass transit plan leading the way.
Brad Freeze, director of the Tennessee Department of Transportation’s Traffic Operations Division, also holds a wait-and-see perspective.
“Transportation agencies like TDOT will have a role in making autonomous driving systems work together to achieve their full potential on our roadway infrastructure,” he said. “In addition, TDOT will be heavily involved in managing the transition related to self-driving systems. Autonomous vehicles initially will need to be integrated into mixed traffic, which could present challenges not fully realized.”
Freeze said it’s also challenging to implement transportation upgrades that are needed today, while making sure they can mesh with future autonomous technology.
Hafkenschiel, who shared similar concerns, described a nightmare traffic scenario of thousands of autonomous cars circling downtown Nashville looking for a parking space. She added that costs and inclusiveness must also be addressed.
Asked about the timeline for introducing autonomous vehicles to Nashville’s roadways, Hafkenschiel said it all depends on the level of autonomous vehicle.
According to SAE International, formerly the Society of Automotive Engineers, the levels of driving automation are: no automation (0), driver assistance (1), partial automation (2), conditional automation (3), high automation (4) and full automation (5).
Hafkenschiel said it’s shocking to see what high-tech cars are already capable of doing. Level 3 vehicles are on the street in Tennessee, but levels 4 and 5 take automation to uncharted territory.
“I think we are all waiting to see when the level 4 and 5 vehicles will come to Tennessee,” she said.
Freeze said he anticipates more autonomous vehicles will scatter the roadways in the next five years, with the first broader implementation likely appearing in private micro-transit settings, like transportation startups and public transit services.