Tesla Motors Inc. delivered 14,370 vehicles in the second quarter, missing its forecast of 17,000 units because of what it called "extreme" ramp-up in production.

The maker of electric cars and energy storage devices now expects to deliver 50,000 cars in the second half, according to a statement Sunday. That means 79,180 Model S sedans and Model X sport utility vehicles shipped for the full year, slightly below its previous range of 80,000 to 90,000.

Tesla is ramping up production at its Fremont, Calif., factory with an eye toward making 500,000 cars a year by 2018. The smaller, less-expensive Model 3 car, which is slated to start at $35,000 before incentives, is scheduled to begin deliveries in late 2017.

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On Friday, U.S. regulators began a preliminary investigation into a fatal May crash involving a Model S that had Tesla's autopilot feature engaged. In a blog post, Tesla said that the crash was the first known fatality in more than 130 million miles of autopilot driving and that the feature, disabled by default in the cars, requires explicit acknowledgment by drivers who enable it that the system is new technology still in testing. At least 70,000 Tesla vehicles worldwide have the autopilot feature, and the fatal crash has drawn renewed attention to the debate over what kind of guidelines the National Highway Traffic Safety Administration should set regarding semi-autonomous and self-driving cars on U.S. roads.

Tesla is also contending with investor fallout after its $2.86-billion (U.S.) all-stock offer to acquire SolarCity Corp. last month. Tesla CEO Elon Musk is SolarCity's chairman and largest shareholder.

The second-quarter deliveries figure is a preliminary number that may change slightly in August when the Palo Alto, Calif.-based company reports earnings for the period. Tesla counts a vehicle as delivered if it's transferred to the buyer and all paperwork is correct. The company releases global sales figures quarterly, instead of the monthly country-by-country results typically announced by other automakers.