Sensors monitor the road and nearby objects, turning the wheel automatically to avoid obstacles. "Most accidents are caused by human error," Nissan says.

Video: Nissan showcases 'self-driving' car

Vehicle makers are working to integrate cars and houses, with the vehicle able to power the home - especially useful in times of blackouts caused by natural disasters.

Honda is showing off a mock installation in which a motorbike powers a gigantic kettle. "Welcome to the future garage that Honda has designed. This is how automobiles and communities will be connected," says Honda president Takanobu Ito.

Many firms have their eyes on the 2020 Tokyo Olympics and the possibilities their technologies could offer by then. Public broadcaster NHK showed off an ultra-high-definition 8K screen, which has around 8,000 pixels on each horizontal line.

"We plan to do experimental broadcasting in 8K by 2016 and we are currently trying our best to be ready to broadcast directly in 8K in 2020", in time for the Tokyo Olympics, says NHK senior engineer Hironori Domen.

Other electronics makers were displaying high-resolution televisions, with Panasonic focusing on 4K devices, including some 20-inch tablets.

"We are displaying 20-inch 4K tablets, which make it possible to integrate what we have seen on paper prints, picture images and movie footage," says Panasonic president Kazuhiro Tsuga. "This is a potential that 4K displays have. Manufacturers will have to widen this potential beyond televisions," he says.

Augmented reality, 3-D renderings that seemingly exist in the real world, was a big theme at the fair. Pioneer showcased new navigation systems that can direct drivers to vacant parking spots with signs that appear in front of them.

Car electronics maker Clarion has a sat-nav capable of carrying on a conversation with the driver, and reminding him or her to take a break. "You have driven for a long time. How about a cup of coffee? There is a nice cafe nearby that offers tasty sweets," it says.

The system, powered by Google, also finds restaurants by price bracket, offering suggestions when the driver tells it: "I would like a place where I can have lunch for 1,000 yen [HK$80]."

NTT DoCoMo demonstrated augmented-reality spectacles that can translate a menu in real time.

Its latest development combines cameras, computers and know-how to give the wearer a different view of what they are looking at. The gadget overlays the wearer's first language onto unfamiliar text.

Agence France-Presse