Opens Dec 10 — Elon Musk (@elonmusk) October 22, 2018

Opening event that night & free rides for the public next day — Elon Musk (@elonmusk) October 22, 2018

It's important to remember that Elon Musk tweeting a date doesn't actually mean that this will happen; a Twitter follower even went as far as to ask whether this was in "real time" or "Elon time," referring to the fact that Musk tends to overpromise when it comes to schedules. His response:

I think real — Elon Musk (@elonmusk) October 22, 2018

This is just a test tunnel, but if it works, it will serve to prove the concept and increase interest in these types of tunnels to ease city congestion. The Boring Company is already working on a tunnel between DC and New York, and is aiming to begin digging one between Los Angeles and San Francisco next year. The latter has been pitched as a true hyperloop with pressurized pods, rather than just a high-speed tunnel.