BEIJING • China has unveiled a design concept for a "straddling bus" that will not only save road space but also help reduce air pollution, the official Xinhua news agency reported yesterday.

Also known as a land airbus, the track-based vehicle is designed to be high enough to let cars pass under it.

The concept is the brainchild of Beijing-based firm Transit Explore Bus, which showed off its design at the 19th International High-Tech Expo in Beijing over the weekend.

The passenger compartment spans two traffic lanes and sits high above the road surface on a pair of stilts, leaving the road clear for ordinary cars to pass underneath.

Cars under 2m high can easily pass through regardless of whether the bus is moving. And it can carry up to 1,400 passengers, while travelling at a top speed of 60kmh, running along special tracks.

"The biggest advantage is that the bus will save lots of road space," said Mr Song Youzhou, chief engineer of the project.

He added that the bus performs similar functions as the subway, but at only 16 per cent of the cost. The lead-time to manufacture and construct the bus is also much shorter. Another added benefit is that the design is environmentally friendly.

The electrically powered straddling bus could replace about 40 conventional buses, potentially saving more than 800 tonnes of fuel annually and reducing 2,480 tonnes of carbon emissions, Mr Song said.

Mr Song has been working on exactly such a vehicle for at least six years, the New York Times reported. He had unveiled a similar model in 2010, working with a company known as Shenzhen Huashi Future Parking Equipment. That model also grabbed international headlines, but the project was never realised.

This time, the company working with Mr Song is building a life-size model in Changzhou, a city in eastern China, to test the feasibility of the design. The life-size model is scheduled for testing some time in July or August.

Some Chinese cities have shown interest in the invention, according to Xinhua.

"Our first test bus is planned to be put on track in Qinhuangdao (a port city in north-eastern Hebei province) at the end of July or in August," Mr Song said.

If successful, the straddling bus could ease traffic congestion and help reduce air pollution in China. Local governments in China have previously announced plans to introduce parking regulations and number plate restrictions in a bid to ease congestion.