Other mayors seemed enthusiastic about the potential project by Musk's Boring Company, but many Floridians were quick to point out how shallow the water table is in the state's swampy south.
"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," the tech tycoon tweeted Monday, adding he had discussed the project with Florida Governor Ron DeSantis last week.
Musk was responding to a tweet from Miami Mayor Francis Suarez inviting him to the city to discuss "potential solutions for the benefit of our future."
"If Governor & Mayor want this done, we will do it," Musk tweeted.
@FrancisSuarez @CityofMiami Cars & trucks stuck in traffic generate megatons of toxic gases & particulate, but… https://t.co/JcQIaCxJno— Elon Musk (@elonmusk) 1610960196000
Miami-Dade County Mayor Daniella Levine-Cava chimed in, tweeting, "Let's talk," and Fort Lauderdale Mayor Dean Trantalis said his city also "would love to be apart of this discussion."
The exchange comes amid Suarez's push to lure Silicon Valley investors and tech developers to Miami.
But many were skeptical of digging tunnels in swampy terrain prone to flooding due to rising sea levels.
"It doesn't seem very smart and it is certainly going to be expensive," Kurtis Gurley, a professor of structural engineering at the University of Florida, told CBS Miami.
There's a reason that Floridians haven't built basements to shelter from hurricanes, despite the storms' prevalence in the region.
"Aquaman must be the project manager," joked Wilkine Brutus, an NPR affiliate reporter, on Twitter.
@elonmusk @FrancisSuarez @CityofMiami @boringcompany @RonDeSantisFL Aquaman must be the project manager.— Wilkine Brutus (@wilkinebrutus) 1611067322000
"This is probably the most important and innovative human being alive today but somebody ought to explain the geology of Florida to him before some incredibly stupid shit happens," tweeted Michael Grunwald, a reporter in Florida for Politico.
This is probably the most important and innovative human being alive today but somebody ought to explain the geolog… https://t.co/oYMUWHRmb2— Michael Grunwald (@MikeGrunwald) 1610989351000
Florida sits on a porous limestone plateau with plenty of open or subterranean canals, and is prone to flooding and sinkholes -- cavities that appear suddenly due to groundwater erosion.