With elderly drivers blamed for five serious traffic accidents in recent weeks, Massachusetts lawmakers are considering plans to tighten the regulations governing older motorists. Their concern is well founded.

Among the accidents, an elderly driver struck and killed a 4-year-old girl in Stoughton. A 93-year-old man crashed into a Walmart in Danvers, injuring six people. And in Plymouth, a 73-year-old woman ran into a crowd at a war memorial.

The dangers posed by elderly drivers are a problem nationwide. For many, the question is whether they should be driving at all, much less given 25-percent discounts in auto-insurance premiums, as required by Massachusetts law.

The Automobile Insurers Bureau of Massachusetts has found that older people under 75 are actually safer than other drivers, hence the discounts. But after 75, the risks they pose soar. Let’s face it. With age, our reaction times and cognitive abilities go into decline.

The solution, clearly, is to assess who can safely drive and who cannot, rather than create an arbitrary age cutoff. People age very differently, with some still fully functional at 90. State Rep. Joseph F. Wagner told a State House hearing that the legislature, in considering a comprehensive bill, would focus on drivers’ ability to function behind the wheel, not just age.

Massachusetts does need a test tailored for older drivers, rather than the simple eye test, standard for renewing a driver’s license. Now, motorists must renew their licenses every five years and take an eye test every 10. Twenty states, Rhode Island among them, demand that drivers 75 and older renew their licenses every two years. Only New Hampshire and Illinois require road tests for drivers that age.

In some states, doctors must report patients who might be unable to safely negotiate the roads. That’s not the case in Massachusetts, though its doctors have to clear drivers for disabled parking privileges. And when drivers are tagged for causing crashes, they must take medical and road tests.

Clearly, there are many ways to approach the problem. One is to enhance public-transportation systems and encourage housing along their routes. The spread-out nature of much development has made Americans overly dependent on the automobile. It hobbles the mobility of young teens as well as their grandparents, many of whom would rather not be driving.

Better monitoring of elderly drivers needs to be put in place now, because the challenge will only get worse with changing demographics. By 2025, a quarter of all drivers will be over the age of 65, says the Insurance Institute for Highway Safety. That’s something to think about.