Nearly 60,000 drivers aged 75 and over were judged to possibly have dementia when renewing their licenses in the first year of stricter screening for elderly drivers, the National Police Agency said Thursday.

The revised road traffic law, which requires elderly drivers to see a doctor if dementia is suspected during a preliminary screening, took effect on March 12 last year. Fatal crashes involving senior citizens have become a major issue due to the rapid aging of the population.

The agency said in a report that 2,105,477 holders of driver’s licenses took cognitive function tests in the first year of the revised law, and 57,099 of them were suspected of having dementia.

A total of 1,892 of those drivers had their licenses suspended or nullified, up about threefold from 597 in 2016. A further 16,115 gave up their licenses after being judged as possibly having dementia, while 4,517 people stopped their renewal procedure and their licenses became null and void.

Some 1,515 others are still in the middle of their renewal procedures, suggesting the number of suspensions and nullifications is likely to grow.

Overall, 151,528 people in Japan voluntarily returned their licenses to the police between January and April this year, with some 70 percent of them (105,560) age 75 or older, according to preliminary data from the NPA.

Before the law’s revision, doctors’ diagnoses were encouraged but not mandatory when dementia was suspected in cognitive tests.

The number of traffic deaths in Japan has been on the decline, dropping to a record-low of 3,694 people in 2017. But serious accidents caused by elderly drivers have continued to attract national attention, particularly as the country is expected to have more elderly drivers in coming years.

Last month, a 90-year-old woman was arrested after allegedly running a red light and hitting four pedestrians in Chigasaki, Kanagawa Prefecture. One of the pedestrians died.

The latest police tally showed 13,063 drivers were allowed to continue driving after seeing doctors, but 9,563 of them are required to have another medical exam conducted in six months as their cognitive functions are seen to be deteriorating.

The number of people feared to be experiencing lower levels of deterioration in their cognitive functions and who were not required to have a medical examination totaled 553,810, while 1,494,568 didn’t show any signs of cognitive problems.

As alternative transportation services for the elderly who give up their licenses are limited, the NPA set up an expert group last October to study whether to introduce driving permits that would limit where, when and what type of vehicles senior citizens can drive. Such licenses have been issued in Europe and the United States.

An NPA official said the agency also plans to ask automakers how advanced safety technologies might make up for the deterioration in the driving skills of the elderly.