WASHINGTON, DC - APRIL 23: Googles Lexus RX 450H Self Driving Car is seen parked on Pennsylvania Ave. on April 23, 2014 in Washington, DC. Google has logged over 300,000 miles testing its self driving cars around the country. Mark Wilson/Getty Images/AFP

Ypsilanti, Michigan - Your car soon will do more to help avoid a crash. As for one day leaving all the driving to the vehicle while you relax in back, don't get your hopes up.

That's the message from safety executives at Toyota, who on Thursday promised by 2017 to have collision-prevention technology installed across its US line-up, in both mainstream Toyota and luxury Lexus vehicles.

But for now at least, every vehicle the company designs and builds will require somebody in the driving seat.

Toyota expects by “mid-decade” to roll out a next generation of safety systems in the US that allow cars to steer themselves enough to stay in the centre of a lane. And to keep the driver focused on the task at hand - driving - the cars will also feature a camera that monitors the driver's eyes and makes sure that hands are on the steering wheel. If the eyes drift off the road or hands come off the wheel, the car would issue a warning.

“In other words, a full-time back-seat driver.”

Several other automakers already have lane-steering technology and driver monitoring systems, but often they're only available in higher-cost or luxury models.

Ken Koibuchi, general manager of Toyota's intelligent vehicle division, said at Thursday's briefing Toyota's system might eventually have the ability to warn you if your freeway lane is going away, or merging traffic could hit your car.

That technology was still being developed and was limited by mapping data nationwide, the safety executives said at a safety briefing near Ypsilanti, Michigan.

The company sees a gradual shift toward cars doing most of the driving work, with each increment helping people to gain trust in the automated systems.

Toyota says the industry is more than a decade away from making a car that could drive itself, due to technology limitations and legal issues. And unlike Google, Toyota doesn't see the day where a human won't be needed behind the wheel.

“Toyota will not be developing a driverless car.”

Seigo Kuzumaki, the company's deputy chief safety technology officers, said humans would still be needed to handle situations that could’t anticipated by a computer.

Toyota and other automakers already have radar-activated cruise control that keeps a safe distance from other traffic and can even stop the car when needed if the driver doesn't react. The next-generation Toyota system will have more sensitive radar that can see farther and react faster.

Toyota plans to put collision-prevention systems on all cars in its US model lineup by 2017. The systems are likely to include the radar-activated cruise control, although Toyota said details will be released closer to launch. The radar system now is available as an option on all Lexus and six Toyota models.

Toyota's safety briefing came ahead of next week's Intelligent Transportation Society of America World Congress in Detroit, where many automakers and parts suppliers plan to show off new safety technology.