More than half of recorded incidents suspected of being sudden unintended acceleration have involved drivers under the age of 60, government data showed Wednesday, contrary to the spreading belief that many such cases are caused by operator error on the part of older drivers.

There have been 456 reports of SUA in South Korea from 2014 through last month, according to a Korea Transportation Safety Authority report submitted to Rep. Ahn Tae-jun of the main opposition Democratic Party of Korea. The age of the driver had been verified in 396 cases, of which 122 were in their 60s, 46 were in their 70s and three were in their 80s.

But the report also showed that 108 reports were submitted by drivers in their 50s, 80 by those in their 40s, 30 by those in their 30s, and seven by 20-something drivers. While such cases occurred more frequently among older drivers, the data shows it is not an issue exclusive to them.

In light of the July 1 car crash near Seoul City Hall by a 68-year-old driver, which left nine dead and four injured, concerns have been growing over the driving capacity of senior citizens. Calls have intensified for the government to revisit its plans to issue conditional driving licenses for seniors, which it suggested in May but scrapped following public backlash.

Along with the controversy has come ballooning suspicion against the claim of sudden unintended acceleration made by the driver behind the wheel of the July 1 tragedy. Some have speculated it was not a braking problem that caused the accident as he claimed, but his own human error.

Experts have raised caution against such public perception. "SUA accidents occur frequently in all age groups. ... The City Hall crash had fueled misperception that such accidents mostly involve older drivers," Kim Pilsoo, a professor who teaches automotive engineering at Daelim University, told local media.

Kim stressed that the policy should focus on expanding the implementation of automotive devices that can prevent SUA, such as automated emergency braking systems, rather than to focus on the issue of elderly driving itself.

The driver responsible for the fatal car crash is currently being investigated by police. He told investigators that he did hit the brakes, but they were "stiff" and did not function.