Tesla Motors said on Sunday it was updating the Autopilot driving systems in Model S sedans to put new limits on its hands-free operation, which has been both praised for its innovation while criticized for having been launched too early.
The function will now be restricted on residential roads or roads without a center divider, meaning the car cannot drive faster than the speed limit maximum plus five miles (8 km) per hour.
Tesla Chief Executive Elon Musk said the car will now reduce its speed in anticipation of curves on the highway, but added he was not aware of any accidents caused by the earlier version of the software.
Tesla announced the Autopilot upgrade the day before the start of Detroit's North American International Auto Show, where traditional carmakers - which in general have lagged Tesla in unveiling semi-autonomous technology - launch new models.
When Autopilot launched in October, Musk cautioned the hotly anticipated function was in beta mode, or a test phase of development, with full 'hands-off' driving not recommended.
Still, a host of subsequent videos posted by Tesla drivers on YouTube showed near-misses on the road with Autopilot, prompting Musk to say he might curb the function to minimize the possibility of people doing "crazy things."
The U.S. pioneer in luxury electric cars charged by batteries was one of the first companies to offer steering that could be operated hands-free, one of the first steps to full self-driving that industry experts say may be available by 2020.
In an interview with reporters, Musk said Tesla's system was "probably better than human at this point in highway driving," able to keep to its lane using cameras, radar and mapping.
The company's expertise in software has allowed it to add the hands-free functionality - and to correct any glitches - through a software update, but critics have suggested the company should have delayed Autopilot until it was perfect.
At the Consumer Electronics Show in Las Vegas last week, the head of GM's global product development, Mark Reuss, said his company would "never" use over-the-air upgrades in safety-critical systems like steering and braking.
Tesla said improvements were made to help the car better stay in lanes even with faded markings, and when passing highway exits. In cruise control mode, the car will now anticipate exits by slowing down if the turn signal is activated.
Using a feature called "summon," Model S drivers can park their cars from outside the vehicle in tight spots and the cars can also park themselves in perpendicular spots to the curb.
In a bold pronouncement characteristic of Musk, who also has interests in space travel, he said advances in the "summon" technology would allow Tesla owners to summon their cars from New York to Los Angeles within two years.
(Reporting By Alexandria Sage; Editing by Keith Weir and Bill Rigby)