DETROIT — Some Tesla Motors vehicles can park themselves without a driver inside with a software update beamed to customers over the weekend.

The update also puts new speed limits on Tesla’s semi-autonomous Autopilot mode and makes several enhancements, including automatically slowing when the car is approaching a curve and keeping the car in its lane even when the lane markings are faded.

CEO Elon Musk said the parking feature is a “baby step” toward his eventual goal: Letting drivers summon their self-driving, self-charging cars from anywhere using their phones.

“I actually think, and I might be slightly optimistic on this, within two years you’ll be able to summon your car from across the country,” Musk said on a conference call. “This is the first little step in that direction.”

For now, though, the system isn’t truly autonomous.

Owners must line up their Model S sedan or Model X SUV within 33 feet of the space they want it to drive or back into. They must then stand within 10 feet and direct the car to park itself using the key fob or Tesla’s smart phone app. The car can also exit the spot when the driver summons it. If it’s going into a home garage, it can also open and close the garage door.

Tesla says the system is helpful for tight parking spots.