The Boring Company’s tunnel vision is coming to life, but it’s now only open to autonomous cars. Founder Elon Musk took to the stage by the firm’s 1.14-mile test tunnel on Tuesday, where he outlined a vision for narrow, easy-to-construct routes that enable autonomous cars to let loose and whizz along at speeds of up to 150 mph.

The idea differs somewhat from Musk’s previous outlines, which used an electric skate to move any car through the tunnels at speed, and could be fitted with a passenger cabin holding up to 16 people. With this new proposal, autonomous cars would use guide wheels that drop down from the front to hold the car in place. However, Musk was keen to stress that “this is not intended to be some sort of walled garden, or just for Teslas or something like that,” adding that “any autonomous EV can be outfitted with these guide wheels.” The use of autonomous cars means the company can reduce the tunnel diameter from the 28 feet of a regular one-lane tunnel to under 14 feet.

A Tesla Model X with guide wheels. The Boring Company

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The announcement is the culmination of almost two years work, when the firm was officially founded as a means of reducing Los Angeles traffic. The plan is to build an array of tunnels around 10 times cheaper than current projects, with tunneling machines using triple the power of existing designs. Cars would drop through using either elevators, spirals or ramps, flipping out the guide wheels to take off. The system would support around 4,000 cars per hour.

Although the tunnels will only support autonomous cars, Musk has a plan to still enable people without a car to get across town. Pedestrians and cyclists can call on ready-supplied vehicles, which would take priority over other cars using the tunnel. Demonstration shots use a Tesla Model X, which supports up to seven seats. The company also claims it wants to complement existing public transit systems.

While any autonomous car can use the system, the question is when these vehicles will hit the roads. Tesla claims its cars already ship with the necessary cameras and sensors to enable full autonomous driving, while Anthony Levandowski announced this week that he completed a coast-to-coast ride using an aftermarket setup with zero disengagements. There aren’t many autonomous cars on the road right now, but The Boring Company may have come at just the right time.

Related video: The Boring Company Demonstrates Its Radical New Tunnel Idea