In China's booming sport utility vehicle (SUV) market, many automakers are selling cars without electronic stability control (ESC) as a standard feature, potentially putting lives at risk from rollover accidents.
SUV sales topped 6 million in China last year, a jump of more than 50 percent in an overall market that grew less than 5 percent, as drivers sought more room for their money. As China's economy weakens, price-conscious drivers have shifted from foreign brands to cheaper domestic SUVs.
To make the sale, many automakers and dealers only offer ESC as an extra, more expensive, option.
SUVs have a higher centre of gravity putting them more at risk of rolling over. ESC counteracts that, quickly reorienting a skidding vehicle to stop it from rolling. A study published by Annals of Advances in Automotive Medicine found vehicles with ESC are two-thirds less likely to flip.
There is no legal requirement in China for ESC, and German parts maker Bosch says 43 percent of SUVs do not come equipped with this technology.
Industry experts note that China, the world's biggest autos market, similarly doesn't legally require anti-lock brakes, and other developing markets including India and Mexico do not require air bags.
In 2007, following a series of SUV rollovers, the United States ordered ESC to be compulsory in all passenger vehicles. The U.S. National Highway Traffic Safety Administration (NHSTA) estimated the change saved more than 2,200 lives over a three year period.
"ESC saves lives," said Chris Harrison, head of China R&D at Continental AG, another German car parts and technology firm.
China's Ministry of Transportation and the Ministry of Industry and Information Technology, generally responsible for regulating the autos industry, did not respond to faxed questions about whether there are plans to make ESC compulsory.
Among the 10 best-selling SUVs in China last year, seven did not have ESC as a standard feature. Those included cars made by Great Wall Motor, Chongqing Changan Automobile , Anhui Jianghuai Automobile (JAC) and Chery Automobile, according to company representatives and officially published specifications.
The three foreign models in the top-10 are universally equipped with the safety feature, but some cheaper foreign SUVs also do not have ESC as standard in China.
BYD Co Ltd , Guangzhou Automobile Group and Geely said some of their models do not have stability control as standard, but it is often available on higher cost packages.
Most of the automakers said their SUVs complied with regulations and reflected consumer demand.
A spokesman for Chery said that with this year's model all its Tiggo SUVs come with ESC. JAC and Guangzhou Auto said sales of SUVs without ESC are very low and were part of a pricing strategy to attract customers. Geely said the majority of its third-generation vehicles have ESC. Great Wall, Changan and BYD declined to comment.
It's hard to gauge whether the lack of ESC in so many SUVs sold in China has contributed to more fatalities.
In the United States, detailed information on every fatal road crash is made publicly available, but in China, crash records and data are often considered state secrets. The World Health Organization estimates China's overall traffic fatalities could be four times the official figure.
The Ministry of Public Security records only fatal rollover crashes on highways and does not break those down for sedans and SUVs. Its latest available data logged 630 rollovers and 403 deaths on Chinese highways in 2014.
In one instance in 2012, a Sante Fe SUV made by Hawtai Motor skidded on a highway at 110 kms per hour (68 mph), crashed through the barrier and rolled three times, killing a passenger and injuring two others, according to documents provided by a car industry researcher. The vehicle did not have stability control fitted.
Last year, a Sportage SUV made by South Korea's Kia Motors and not equipped with ESC skidded and flipped over at 60 kph (37 mph) in snowy conditions, killing one occupant.
Both Hawtai and Kia said their cars comply with all legal requirements and some of their SUV models do have ESC. Hawtai acknowledged that cars without ESC are less safe, but even those with the safety feature are "not 100 percent safe" because of road conditions and driver habits.
BAIC Motor Corp's Huansu SUVs, among China's 2015 top-10, did not offer ESC before last November, according to BAIC dealers and specifications on the automaker's website.
BAIC sold 181,100 Huansu SUVs last year, according to the China Association of Automobile Manufacturers, with a starting price of just 51,800 yuan ($7,873). In November, BAIC launched its Huansu S6, with ESC optional on cheaper packages, but standard on all but one priced above 96,800 yuan.
Buyers appear either unaware of the risks or of the option to pay more for the safety feature.
"You must give up something if you want a car at that price, so I sacrifice ESC," said Xu Zhou, a Huansu S3 driver in China's southern Hunan province. "If a car has ESC, that's great, but if not, you have to be more careful when you drive."
Another Huansu owner told Reuters he didn't know about ESC when he bought the car, and would buy an SUV with stabilisation technology next time.
A spokeswoman for BAIC Huansu said ESC could be offered in the S2 and S3 SUV models at their next redesign as "this option is more and more important."
With China's SUV market now so competitive, automakers may look to emphasize safety features such as ESC as a way to differentiate, said Chen Liming, a Bosch regional president overseeing the China electronic stability programme.
"People are willing to buy safety products," Chen said.