Reportedly, the tunnel was accidentally crammed with 90 Teslas instead of the maximum of 70 due to “driver error,” causing the epic traffic jam.

The Boring Company
Musk Slated To Be World’s First Trillionaire, Largely Due To His Private Venture SpaceX–Not Tesla
Musk has flirted with bankruptcy more than once, incited many publicly aired lawsuits, and has garnered government scrutiny on several occasions.
Elon Musk’s Vegas Loop Drivers Are Forced To Follow “Ride Script” And Say He’s “Awesome”
If a driver is asked whether they like working for the SpaceX mastermind, they are instructed to say: “Yup, he’s a great leader! He motivates us to do great work.”