(Bloomberg) -- NissanMotor Co. introduced driver-assist features that enable itsnewest minivan to handle some highway driving on its own, just as asimilar system from electric-car maker Tesla Motors Inc. comesunder scrutiny following a number of crashes.

The technology, available in the new Serena model on sale inJapan next month, renders the minivan capable of accelerating,braking and navigating highway stop-and-go traffic in a singlelane. Called ProPilot, the system sends warnings whendrivers take their hands off the wheel and will eventually disableif the prompts are ignored for a few seconds.

Japan’s Transport Ministry said last week dealers selling carswith driver-assist functions should remind consumers of theirlimits, noted Tesla’s Autopilot system isn’t fully autonomous andsaid drivers should be responsible in the event of accidents. TheU.S.’s National HighwayTraffic Safety Administration is expected to announceguidelines as soon as this month that will set some parameters forself-driving cars.

“The point is it’s not fully autonomous driving, but driverassistance technology, so it can’t handle everything for you,”Hideyuki Sakamoto, a Nissan executive vice president, saidWednesday during a briefing in Yokohama.

Regulators are scrutinizing Tesla’s similar Autopilottechnology after an Ohio man died when he and his Model S sedanfailed to react to an 18-wheeler crossing a Florida road in May.Nissan’s Sakamoto said while he didn’t understand Tesla’s Autopilotwell, in a similar situation, ProPilot “should be able to functioncorrectly.”

Pennsylvania State Police have since cited the driver of a Tesla Model X involved ina July 1 crash that may have involved Autopilot technology forcareless driving, according to a report released Monday.

Another Tesla driver has told Montana police that Autopilot wasengaged during an accident that occurred on Saturday. The carmakerconfirmed Autopilot was engaged when the car drove off the side ofthe road, though the driver didn’t put his hands on the wheel inspite of the vehicle alerting him to do so, Tesla said Tuesday.

Managing expectations

“The challenge for automakers is to clearly articulate thoselimitations and manage the expectations of their customers,” saidJeremy Carlson, a Los Angeles-based analyst for IHSAutomotive. “That’s only going to become more difficult whenrapidly evolving technology means a Nissan may behave differentlythan a Tesla or Toyota in the same situation.”

Nissan’s release of ProPilot follows more premium brandsincluding Tesla, Daimler AG and Volvo Car AB, whose technologiesallow their vehicles to handle more complicated trafficconditions. Nissan plans to extend the availability ofProPilot to Europe with the Qashqai sport utility vehicle, as wellas to the U.S. and China.

Toyota Motor Corp., Honda Motor Co. and Fuji Heavy IndustriesLtd. all plan to introduce vehicles capable of driving themselveson highways by 2020. The Renault-Nissan Alliance has said it plansto launch more than 10 vehicles with autonomous-drive technology inthe next four years.

Step-by-step

Nissan plans to add autonomous-driving functions step-by-step,enabling cars to change lanes on their own in 2018 and traverseurban roads, including intersections, by 2020.

The ProPilot system available on the Serena uses a monocularcamera supplied by ZF TRW Automotive Holdings Corp. to detectobstacles and relies on a system jointly developed with Mobileye NVto process images, said Kiwamu Aoyanagi, a Nissan engineer. Pricingdetails will be announced later, he said.

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Nissan will make sure dealers will inform drivers of itstechnology’s limits and ensure they understand it’s not aself-driving car, spokesman Nicholas Maxfield said.

Nissan has been “clearer than most” in outlining how it intendsto bring technology to market and describing precisely what it willdo, IHS Automotive’s Carlson said. “That’s something that many massmarket competitors have not always communicated very clearly.”

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