Your lead editorial Dec. 11 about senior driving was a helpful description about the complicated issues faced by the Bureau of Motor Vehicles, senior drivers and their families. However, it overstates the magnitude of the problem when it asserts that “the accident rate stays flat until the driver reaches retirement age, after which it starts to rise again to mirror and then exceed that of teenage drivers. In fact, drivers age 70 and older are involved in more crashes per mile driven than any age group.”

The way one measures outcomes makes a big difference in how senior drivers (generally older than 70) compare to teenage ones: crashes or fatalities, by driver or by estimated 100,000 miles driven. Both national and Maine data consistently show crash rates per driver for seniors up into their 90s insignificantly different from middle-age drivers. Crash rates per estimated 100,000 miles driven for drivers 75-80 are modestly (1.5-3 times) higher than for middle-age drivers, whereas teen drivers are more than six times higher.

Fatalities per driver, however, do jump markedly after age 75, and by 90 approach the fatality rates seen in 16 year olds. The frailty of the elderly plays a larger role in these fatalities; crashes of similar severity are more likely to kill a senior older than 75 and/or his peer-age passengers than a teenager and his companions. Most studies estimate this frailty effect of aging as contributing 50 percent to 75 percent of the increased fatality rate for elderly drivers. Better car and traffic design also help all age groups dramatically.

But senior driving issues are significant, especially for the drivers themselves. Self and family identification, Bureau of Motor Vehicle policy changes, community reporting and better public transportation systems all need to be buffed up, as the editorial suggests.

Daniel K. Onion, M.D.Maine Senior Driver CoalitionVienna