• A Tesla Model S car is displayed at a Tesla showroom on November 5, 2013 in Palo Alto, California.

A Tesla Model S car is displayed at a Tesla showroom on November 5, 2013 in Palo Alto, California. (Photo : Getty Images/Justin Sullivan)

Tesla is now offering free trials of its autopilot software for all Model S and X vehicles manufactured after September 2014, as the cars already contain the needed equipment, such as a radar system, a front-facing camera adjacent to the rear-view mirror and 12 sensors, which can sense objects within 16 feet from the car.

Like Us on Facebook

Tesla launched its autopilot in October 2015, enabling its cars to steer, parallel park or change lanes on highways. Furthermore, there are safety features like the warning system for side collisions. The autopilot needs only minimal input from the driver as it relies on computer hardware and software, Fortune has learned.

The automaker offered the autopilot to customers via an over-the-air software download with an extra fee. However, the company said customers can now download the software without the fee and access it for a month.

Earlier this month, Joshua Brown from Ohio took his Tesla Model S to get familiar with the autopilot system, how it takes over of the vehicle and avoid a crash. His video in YouTube recounted what happened when a heavy truck with a hydraulic lifting system which he was not aware, nearly sideswiped him, MarketWatch reported.

Brown was driving down the interstate and saw the boom lift truck on the screen's left side on a joining interstate road. When the roads met, the truck tried to go to the exit ramp on the right, and did not see his car, which he calls Tessy.

"I actually wasn't watching that direction and Tessy was on duty with autopilot engaged," Brown said in the YouTube video. "I became aware of the danger when Tessy alerted me with the 'immediately take over' warning chime and the car swerving to the right to avoid the side collision."

The Ohioan said he has tested Tessy's software capabilities and sensors a lot of time, but until that time, "had not tested the car's side collision avoidance." The car has been with him since July 2015 and said he has logged about 39,000 miles.

Here is Brown's YouTube video with his Tessy car: