Tesla plans to build a new pick-up truck, and an urban bus, and launch a sharing system of self-driving cars, the company's founder Elon Musk announced Wednesday.

The projects are part of what the billionaire entrepreneur called a "secret" second master plan for the US electric car manufacturer posted on the company's website at a time it is looking to rebound from concerns over the safety of its "Autopilot" semi-autonomous driving mode.

"In addition to consumer vehicles, there are two other types of electric vehicle needed: heavy-duty trucks and high passenger-density urban transport," Musk wrote. "Both are in the early stages of development at Tesla and should be ready for unveiling next year."

He also restated his ambition to make all Tesla vehicles completely autonomous -- capable of driving without a human driver.

Once regulators approve the technology, he said, "you will also be able to add your car to the Tesla shared fleet just by tapping a button on the Tesla phone app and have it generate income for you while you're at work or on vacation."

"In cities where demand exceeds the supply of customer-owned cars, Tesla will operate its own fleet," he added.

The new road map follows a first master plan Musk unveiled in 2006, when he promised "an electric car without compromises" and a long-term vision of building "affordably priced family cars."

Tesla Motors launched its first electric car in 2008 called the Roadster, which had limited distribution, followed in 2012 by the Model S, which has gained appeal globally among well-heeled buyers willing to pay some $70,000 or more.

Profits from those models have enabled the company to begin plans for its more affordable Model 3, at roughly half the price of the Model S, for which it has already received more than 300,000 pre-orders.

But Tesla's reputation has been hit by a fatal crash involving its self-driving system in Florida, and another crash in Pennsylvania, prompting federal safety investigations.

Musk -- the South African-born co-founder of PayPal who also runs the private space exploration firm SpaceX -- also outlined a plan to provide easy-to-use solar energy through SolarCity, a company Musk wants to merge with Tesla.

"What really matters to accelerate a sustainable future," he wrote, "is being able to scale up production volume as quickly as possible."