It's all part of The Boring Company's broader effort to develop a system of tunnels that could create the infrastructure needed for alternative mass transit.
Musk first had the idea to build congestion-dodging tunnels under LA while stuck in traffic in December 2016.
The test tunnel will stretch almost three miles along Sepulveda on LA's Westside, one of the most traffic-congested parts of the city.
This evening, Boring Company executives Elon Musk and Steve Davis offered a few more details about their plans to revolutionize LA urban transit, introducing the "Loop" which would eventually be composed of all-electric pods that transport up to 16 passengers at a time.
The West L.A. tunnel is the latest project Boring has undertaken after quietly digging a slightly shorter tunnel underneath tiny neighboring municipality of Hawthorne, where SpaceX and Boring are both headquartered.
That plan has been met with skepticism (and a lawsuit) by neighborhood groups concerned about construction noise and other environmental impacts.
Known for aggressively taking on large-scale technical challenges with which he has had little previous experience, Musk ended his pitch on a humble note, telling the audience that realising his vision "could only happen with public support". They would be dug at a minimum of 30 feet to 60 feet underground, way below utilities.
Musk said that Boring Company Loop's vision of the future would be much more congruous with city life than subways, and that while it was very hard to weave large stations into a city, building many more parking spot-sized stations could theoretically be much more effective. "We can actually sell the bricks at like 10 cents a brick", Musk said.
He said he was largely inspired by the "soul-sucking traffic on the 405". The tunnel would run southward under Sepulveda Blvd. and would end, without surfacing, below the vicinity of the intersection of Sepulveda Blvd. and Washington Boulevard in Culver City. The site of that test tunnel is ensconced in a largely affluent part of the city, where locals are typically averse to projects that might disrupt daily life.
"Compared to a flying vehicle, you don't have to worry about bad weather, you can't see it, hear it, feel it".
"We are going to do everything right".
Possibly at some point quickly we'll discover out.