A Beijing woman is suing BYD, the car company owned by China's richest man, because the airbags on her car failed to activate during a collision.

Huo Yanhong told Beijing Second Intermediate People's Court that she bought a 40,000 yuan (US$5,870) from Beijing Wanda Automobile Service Company because it was advertised as having a "5 star" safety system.

However, when a friend who had borrowed the vehicle was involved in a serious rear-end collision the next month, the air bags on the car failed to activate.

Outside court, the woman's lawyer Han Bingsheng told METRO that the Huo's friend suffered concussion and was in hospital for one week after the crash.

Huo is now suing BYD for exaggerated promotion of its safety, he said. BYD and Huo have both expressed a desire to settle out of court and will meet to negotiate in the coming days.

BYD is owned by Wang Chuanfu, who this week was named the nation's richest man with a fortune of more than US$5.1 billion.

His pioneering company, which began a battery maker, has attracted investment from US billionaire Warren Buffet, who has acquired 10 percent of its stock.

Mrs Huo told the court that she browsed many car brochures before deciding on a vehicle. She chose the BYD F0 auto because it was advertised as having "5 star safety".

However, she later learned that the car only received a 3-star rating in a safety test conducted in September by the China Automotive Technology & Research Center.

The test result was released on Sept 24. Among the 18 auto models tested, the BYD F0 cars scored a total of 38.9 out of 51 in collision test. The Peugeot New 307 received a 5-star rating, with Beijing Hyundai Sonata and ChangFeng Motor CS6 awarded 4-star ratings.

Mrs Huo said BYD cheated customers because its F0 model did not have a 5-star rating, and in addition, it did not even have a star rating before September. She asked the court to demand BYD stop making fake advertising claims and for a public apology.

BYD refused to comment when contacted by METRO.

Han said BYD told the court that the "5 star" slogan was just used to show their love for China, because the national flag is composed of 5 stars.

Han said that it was well known in the industry that 5 stars referred to the safety test levels. The company said the F0 car met the national standard and passed the national safety collision experiment.

Speaking outside court, Jia Xinguang, an auto industry expert, said that the national safety check requirement just checked a sample of the car model, and the C-NCAP was not compulsory.

"The national safety check conducted by government acts like a production permit. If you pass it, you can make cars. The C-NCAP test is just a recommended requirement, not all the cars have to under through it," Jia told METRO.

"And what's more, these two test standards are far lower than international standards."

"Without a random inspection from time to time and assessment reports from the customer side, the safety of cars made in China will be largely uncertain."

Also speaking outside court, Li Zhiqiang, director of Beijing BYD Owner Association, a car club, said he bought a BYD F3 car for 67,000 yuan in 2007, but had not experienced safety problems with the car.

"As far as we know, for the F3 car model, the most popular BYD model, our members usually have a good response; but for the new F0 car, we are not that familiar enough with it to talk about it." Li said. "Many people living in Beijing buy BYD now, because of its cheap price."

BYD Co is aiming to become the nation's largest passenger car manufacturer ahead by 2015. It wants to overtake Toyota as the world's No 1 carmaker, and sell more than 10 million cars annually by 2025.