A total of 30,170 drivers ages 75 or older showed signs of dementia, according to the results of a recent cognitive test required of elderly license holders under the country’s revised Road Traffic Law.

In the nearly six months since the law took effect on March 12, about 1.12 million elderly drivers took the test, 674 had their licenses revoked after doctors diagnosed them with full-on dementia, provisional figures released Thursday by the National Police Agency showed.

Under the revised law, drivers who are 75 or older are required to undergo a cognitive test when they apply to renew their licenses and if they commit certain traffic violations.

Those showing signs of dementia under the test are obliged to see doctors and will have their licenses revoked or suspended if they are diagnosed with dementia.

About 2.7 percent of drivers taking the test were judged as being at risk of having dementia. Of the 7,673 such drivers who were ordered to see doctors by the end of September, other than the 674 who had their licenses revoked, 23 had them suspended.

Some 4,326 drivers were allowed to keep their licenses but were told to submit certificates from doctors again six months later.

A total of 6,391 elderly drivers voluntarily returned their licenses before the test while 1,267 who did not surrender their licenses had them invalidated after failing to see doctors.

The agency previously estimated that about 50,000 drivers annually will need to see doctors following the cognitive test, with the expectation that some 15,000 of them would have to have their licenses revoked or suspended after being diagnosed with dementia.

The actual figures fell short of estimates because many drivers chose to give up their licenses before the medical examination, an agency official said.

Elderly drivers are allowed to retake the cognitive test depending on their health condition at the time they take the first test.

The test results of nearly 4,000 such drivers improved when they were retested.

The agency also said the number of drivers aged 75 or older who returned their licenses in January-September totaled around 184,900, surpassing the 2016 full-year total of some 162,300.

There were 294 cases of fatal traffic accidents involving drivers 75 years or older between January and September, down from 328 from the same period last year, according to the NPA. But it is still high compared to other age groups, it said.

“We would like to further promote comprehensive measures to prevent traffic accidents by elderly drivers,” said NPA chief Masayoshi Sakaguchi during a news conference Thursday.

The police screenings also showed that a majority of elderly drivers, about 780,000, had no problems with their cognitive abilities, while 300,000 were found to have minor issues.

Among fatal traffic accidents involving elderly drivers in recent years, a truck operated by an 87-year-old man in Yokohama near Tokyo ran into a group of school children in October last year, killing one boy, while an 83-year-old woman in Tokyo lost control of her car at a hospital the following month, causing two deaths.

To mitigate the risks associated with dementia, poor vision and deteriorating physical strength associated with seniors, an NPA panel in June proposed several new rules, including limiting them to vehicles with automatic braking systems.

It also urged the government to create a new license that limits seniors to vehicles with advanced safety systems that can automatically brake or prevent unintended accelerations. Seniors could also be restricted to driving at certain times of day or in certain areas.

The panel also recommended continuing ongoing campaigns urging the elderly to voluntarily give up driving.

Similar practices have been put in place in other countries, including the United States and Germany.