Tesla Motors Inc (NASDAQ:TSLA) has finally revealed the ‘D’ secret: it stands for dual motor. The company disappointed many who were expecting Elon Musk to unveil a self-driving car. But the myriad of features showcased at Tesla’s glitzy event on Thursday should pave the way for driverless cars. Now each of the three versions of Model S will be available under the D designation.

Tesla Motors Inc Unveils 'D' With Dual Motor And Autopilot

Tesla is already installing these features in new cars

Elon Musk said the dual engine configuration will improve efficiency, help in better road handling, and boost acceleration. The automated driving system (or autopilot) will prevent accidents, enhance visibility and allow the cars to park themselves. The EV maker has already started installing these features in current production.

Tesla said the dual-motor system takes just 3.2 seconds to go from 0-60 mph.  The autopilot includes a combination of cameras, radar and sonar that are capable of recognizing pedestrians, traffic signals and highway barriers. The autopilot system creates a “protective cocoon” around the car to warn of impending collisions. However, these features won’t make the car fully autonomous.

How much would Tesla’s D variant cost?

Drivers will get sound and visual warnings of impending collisions. And the automated driving system will try to take evasive action, but drivers can overcome the computer’s maneuvers. What’s more, the forward-looking radar will be able to see through conditions that restrict the drivers’ view such as fog, snow and sand. A long-range ultrasonic sonar could detect even a dog or a small child at the risk of being struck by the vehicle.

The dual motor versions of Model S without acceleration boost will cost $4,000 more than the basic and mid-level versions. The 60kWh variant’s price will shoot up from $71,070 to $75,070. The price of 80kWh Model S will rise from $81,070 to $85,070. Deliveries of both these ‘D’ versions will begin in February 2015. The price of the more powerful model will all-wheel drive and acceleration boost, dubbed P85D, will jump from $105,570 to $120,170. The P85D will be available in December.

Tesla shares fell 3.31% to $248.50 in pre-market trading Friday.