Tesla update halts automatic steering if driver inattentive

Tesla Motors says a software update to its Autopilot system will disable automatic steering if drivers don't keep their hands on the wheel.

The update also adds multiple features, including improved radar, better voice commands and an industry-first temperature control system that helps prevent kids and pets from overheating.

Tesla started moving the update to Model X SUV and Model S sedan owners Wednesday night over the internet.

• Tesla updates software to improve radar in wake ofAutopilotcrash
• Tesla was warned about hands-freeAutopilotuse, software maker says

Tesla's Autopilot system, which was unveiled last fall, uses cameras and radar to maintain a set speed, brake automatically and change lanes without the driver's input. Drivers can keep their hands off the wheel for minutes at a time, depending on road conditions. Critics questioned whether the system was ready to be on the road this summer after a driver using Autopilot was killed when his Model S sedan struck a tractor-trailer in Florida.

Tesla says the software update should help avoid crashes, since it will enhance the radar system and make Tesla's vehicles rely more on radar signals which can see through snow, bright sun and other weather conditions than cameras. The new radar can detect braking in cars up to two lengths ahead and has a clearer picture of the road than the previous version. The company also redesigned its indicator lights to more clearly show when Autopilot is engaged.

Three warnings

If drivers ignore three warnings to place their hands on the wheel, the automatic steering will be disabled and won't resume until the car is parked. As in earlier versions, the car will slow to a stop if the warnings are ignored.

It's unclear if the changes will be enough for government regulators, who have been investigating Tesla since learning about the Florida crash. The National Highway Traffic Safety Administration has said that Tesla provided the agency with information about its changes, and the agency is reviewing them.

The software update also allows Teslas to:

• Automatically move around slower vehicles that are partially off the right side of the road;
• Automatically navigate highway interchanges. Previous versions required drivers to turn off Autopilot on off-ramps;
• Automatically adapt curve speeds based on learning from previous Tesla drivers;
• Search for destinations using a single voice command;
• Automatically turn on the air conditioner to keep the car at 40.5 C(105 F)or lower to help protect children or pets.