Tokyo – Japan's demographic time bomb – a surfeit of seniors and a shortage of working taxpayers to support them – is often cast as an economic crisis. But the repercussions of life in the industrialized world's fastest-graying society are playing out in other alarming ways, such as a frightening upsurge in fatal traffic accidents with senior citizens at the wheel.

In heart-rending detail, Japanese media reported on the crusade of a grief-stricken Tokyo man for justice after his wife and young daughter were mowed down along with ten other pedestrians by an 88-year-old motorist. Now facing manslaughter charges, the frail retired bureaucrat plowed into a crowded downtown crosswalk. Police found no evidence to support claims the car had mechanical problems, as the driver claimed.

Among his victims were Mana Matsunaga, 31, and her three-year-old daughter, Riko, cycling home from a day at the park.

Get Breaking News Delivered to Your Inbox

"If my wife was still conscious as she was thrown into the air, her only thought was surely whether our daughter was safe," the sobbing husband and father, who has declined to give his full name, told Japan's TBS TV.

For much of the Japanese public, the tragedy underscored a growing sense that the country is under siege, by its own aged, out-of-control motorists. There is even a grim new genre of dashcam videos, dubbed "rogai," which roughly translates as: "problems caused by senior citizens." The clips posted online feature seniors crashing into buildings, driving the wrong way and otherwise wreaking roadway havoc.

Japan's 75-plus driving population is on course to surpass 7 million in the next few years. An estimated one-quarter of octogenarians are still on the road. Over the last decade, the country has seen more than a 6% rise in fatal collisions caused by senior citizens.

That's despite dementia screening for drivers 75 and over, and local campaigns attempting to coax seniors to give up their driver's licenses, sometimes in exchange for free bus passes or other enticements. The efforts have made little progress, especially in rural areas lacking public transportation.

Just this week the Japanese government approved legislation aimed in part at reducing fatal accidents involving elderly drivers.

Chastened by the backlash, some seniors are going back to drivers-ed. A recent one-day class in Tokyo offered by the Japan Automobile Federation drew 150 applicants for 16 places. Over four hours, seniors negotiated traffic cones, practiced sudden stops, and learned how to ease out of alleys, to compensate for blind spots.

Makoto Danno, 80, concedes that his wife wants him to stop driving, but he says he's not ready, arguing that he's "been driving for years with no complaints."

A classmate in her 70s, Masako Horiguchi, said she felt unfairly tarred by public sentiment against motorists of her generation. Without a car, she said, life would be difficult. "I had a spinal operation," she said, "I can't walk very far."

Sophisticated collision-avoidance systems are becoming common in new car models, but most vehicles on the road here still lack such automated safeguards. So Tokyo now covers the cost of installing after-market devices, which suppress acceleration when drivers mistakenly hit the gas pedal instead of the brake. In a recent test ride at the A-pit Autobacs Shinonome store, manager Chino Naokatsu showed a reporter how the device works during a spin around the parking garage, typical of the low-speed areas where mistaken acceleration accidents often occur. He suddenly floored the gas, but the car crept along at just 6 mph.

Waiting while his car was outfitted with the device, retired air conditioning salesman Kaname Nakayama, 77, said he "couldn't live" without his car, but had capitulated to his family's entreaties. "To be on the safe side, I got it installed."

If the Japanese government has its way, seniors will be trading in their full-sized cars for a cute little vehicle like Toyota's Coms. Resembling a golf cart, it has drafty ziplock doors, no radio, and a single seat for the driver. But with a top speed of 30 mph, the ultra-compact electric vehicle is road-worthy – just enough car for a trip to the store. And, needless to say, far less hazardous in city driving.

The government is weighing subsidizing purchases of tiny cars like this, as it tries to lure more seniors away from their sedans.

The bill approved by the legislature this week would force drivers 75 and over who have driving offenses on their records to pass a road test when they renew their licenses. If approved, it will also make it obligatory for those senior drivers to use only cars equipped with the advanced safety features.