As a solution to Miami’s notoriously congested traffic, Tesla Inc. founder Elon Musk is proposing to dig tunnels with The Boring Company, one of his many business ventures.
Experts say the idea would be costly and is fraught with engineering obstacles, but it’s not outright crazy.
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Musk, who also founded SpaceX and Neuralink, tweeted that he spoke with Gov. Ron DeSantis about the idea earlier this month.
"Cars & trucks stuck in traffic generate megatons of toxic gases & particulate, but @boringcompany road tunnels under Miami would solve traffic & be an example to the world," Musk tweeted. “If Governor & Mayor want this done, we will do it."
Miami Mayor Francis Suarez, a Republican, described the idea as a “no brainer” and replied, “we would love to be the prototype city.”
Miami-Dade Democratic Mayor Daniella Levine Cava and Florida’s Republican chief financial officer, Jimmy Patronis, also expressed enthusiasm.
Critics wondered: How plausible is it to build large tunnels under a city that is only a few feet above sea level, especially with Miami widely regarded as one of the world’s most vulnerable cities to rising sea levels?
“It doesn’t seem very smart and it is certainly going to be expensive,” said Kurtis Gurley, a professor of structural engineering at the University of Florida.
Gurley said one challenge of the project would be keeping water out of the tunnels while shoring up its walls.
The subterranean construction also runs the risk of contaminating Florida’s aquiferm, Gurley said.
But large diameter tunnels are possible in Miami if proper planning and precautionary measures are taken, said Conrad Felice, a professor of civil engineering at the University of Florida.
Felice noted that engineers earlier this decade completed the 4,200-foot Port of Miami Tunnel, which had a price tag of $668.5 million. That tunnel runs 120 feet below the surface.
The Boring Company burrows utility and freight tunnels under cities to alleviate congestive traffic and shave down transportation times. So far, the only completed tunnel is the company’s 1.14 mile, $10 million test tunnel in Hawthorne, California, just outside SpaceX headquarters.
South Florida is largely on a foundation of limestone, which is sponge-like, allowing water to move through it easily. But tunneling through limestone and beneath groundwater is common, said Michael Mooney, a professor of underground construction and tunneling at the Colorado School of Mines.
Mooney said that rising sea levels would increase the pressure on a finally designed tunnel, but that can be accommodated by design.
Sen. Shevrin Jones, D-Miami Gardens, whose district includes south Broward County, said he would rather focus on raising roads, fixing bad pipes and taking serious precautions in a city that is already struggling to combat flooding.
The back-and-forth on Twitter between Musk and Miami’s mayor has yet to be discussed by the city’s professional planning staff, city spokesman John Heffernan said.