PORTLAND — Proposals to require that older motorists undergo additional license renewal tests for vision and mental disabilities may be aired at public hearings in Portland, Augusta and Bangor.

The Task Force to Study the Safe Mobility of Maine’s Aging Population has spent the past year reviewing issues related to safety, mobility and alternative transportation for the elderly.

The panel, made up of state officials and interest groups ranging from the elderly to insurance carriers, plans to present its final recommendations to the Legislature in November.

Proposals likely to stir the most controversy include a requirement that drivers older than 75 renew their licenses every two years, and that drivers older than 40 be tested for vision and mental disabilities at each license renewal.

Under current law, drivers older than 65 are required to renew their licenses every four years and there is no change when a person becomes 75, said Robert O’Connell, director of driver licensing and control for the Bureau of Motor Vehicles.

All other drivers renew their licenses every six years. Visual testing is required every other time a person older than 40 renews a driver’s license.

There is no state test to gauge “cognitive deficit problems” that can hinder a person’s ability to drive, said O’Connell, a task force member.

California is the only state that uses such a screening test, which could identify people with Alzheimer’s disease or a head injury that can alter their behavior, judgment and attention span. It also could help licensing officials determine whether a person is a driving risk, O’Connell said.

Hilton Power, a 72-year-old member of the American Association of Retired Persons, regards additional license tests for the elderly as discriminatory.

A test on cognitive ability is aimed at determining “if you can’t think straight enough to drive,” he said.

Power said using 40 as the age threshold mutes the discrimination issue, but he suggested that it would be even more fair to require everyone to take the tests.

However, Power said he supported many other parts of the draft report released Thursday.

The document includes proposals that could lead to better transportation alternatives and expanded driver safety training for the elderly.

The task force was created last year by the Legislature after lobbying by a Portland woman, Kathleen Freund, whose son was injured by an elderly driver several years ago.

The report noted that Maine drivers, like those nationwide, are involved in far fewer accidents than other age groups. But when measured against the number of miles driven, the accident rate among Maine drivers 75 and older is exceeded only by the rate among teen-agers.

The task force has scheduled hearings on Sept. 23 in Portland, Sept. 30 in Augusta and Oct. 7 in Bangor.