Last month, an 83-year-old Pikesville man turning left into a shopping center on Liberty Road pulled in front of an approaching school bus, causing it to collide with his right rear fender.
The driver of the car, who had been cited for failing to obey a traffic signal several months earlier, was not hurt. Twenty high school students had minor injuries.
"He saw the bus coming and all that. He said he just thought that he had time to make it across the road," said Baltimore County Police Officer Joseph Gibson, the who investigated the crash.
Officer Gibson, 41, has seen a lot of accidents. And he called the Liberty Road mishap typical of those involving older drivers.
While seniors tend to be experienced and careful drivers, he said, some have trouble estimating distance and time, have vision problems or are slow to react to the unexpected.
"It doesn't take much to be off target, and then you are nailed," he said.
Studies by the American Automobile Association Foundation for Traffic Safety and other groups have shown that some older Americans remain good drivers all their lives.
But for others, the skills necessary for safe driving -- night vision, hearing, depth perception, peripheral vision, agility and other faculties -- begin to deteriorate at 55, perhaps dramatically so after 75.
About a decade ago, a number of state motor vehicle agencies adopted laws requiring drivers 65 and older to come in for special testing, said Sam Yaksich Jr., executive director of the AAA Foundation. But some senior groups objected, calling the laws discriminatory, "and states started to back away from it. They haven't stopped retreating," he said.
Today, pressure is again building for state governments to address the issue of older drivers, researchers and others say.
In part, this is because the number of older drivers is growing. In part, it is a result of a number of lawsuits filed recently against state motor vehicle agencies for licensing elderly drivers who later cause fatal accidents.
Mile for mile, drivers over 65 are involved in more accidents and fatalities than any group except those from 16 to 24, according to the AAA Foundation.
And, the foundation said, drivers over age 85 actually have a worse accident-per-mile-driven rate than any other group.
Other studies have shown that because age makes them more vulnerable, seniors are 2 1/2 times more likely to die after an auto crash than younger motorists.
Most accidents involving seniors, researchers say, involve intersections, left turns and freeway ramps -- all of which test judgment of speed and distance, and call for quick reactions.
Many older drivers whose skills have diminished voluntarily cut back on driving at night, in bad weather, on expressways or in heavy traffic, safety researchers say. Or they stop driving altogether.
"I think it's time, when you don't trust yourself, to get out from behind the wheel and let someone else do the driving, even though it's inconvenient as the devil," said Rosa Frances Weigate, 81, of Rodgers Forge, who stopped driving several years ago after having cataract surgery in both eyes.
But some refuse to admit they are less able to navigate an auto, perhaps because, like other Americans, most regard their cars as a symbol of their independence. In many areas, alternative transportation is not available.
"Without a driver's license, they can literally become prisoners in their own homes and communities," said James L. Malfetti, a retired Columbia University researcher who has studied senior drivers for the AAA Foundation.
Meanwhile, the number of older drivers is increasing, in step with thegrowing proportion of seniors in the U.S. population. By 2020, an estimated 50 million Americans 65 and older will be eligible to drive. Half of them will be at least 75.
"I don't know of any responsible individual who says that you should take driving privileges away from older drivers just because they're older," said Stephen Teret, co-director of the Johns Hopkins Injury Prevention Center.
"That wouldn't make any sense, and it wouldn't be constitutional," he said.
"But it may make some sense for motor vehicle agencies to assess the skills of older drivers more frequently than they are doing."
And, he said, vision, knowledge and road testing for seniors, along with everyone else, should be more sophisticated and extensive.
Maryland, Mr. Teret said, "is doing as doing as good a job as any other state does, but I think all of the states need to address the problem more directly."
A 1976 state law in Maryland forbids licensing authorities from using age as a criteria when judging the fitness of drivers.
But all drivers must appear in person for a vision test when they renew their licenses every four years. (Some states permit renewal by mail or have no vision test requirement.)