Should "old" people drive?

After a few close calls with elderly drivers and some annoying experiences, I have caught myself exclaiming, rather loudly, "Old people should not be allowed to drive!!!!"
I, no kidding, followed behind an elderly driver who signaled her intended direction of travel in a curve, but not when she finally decided to turn. I also followed another elderly driver who could not exceed the speed of 20 mph. Luckily, we were in a speed limit zone of 45, and not on the interstate. That was dangerous enough, but it could have been worse. Lately I have encountered elderly people that clearly should not be behind the wheel anymore. If your vision doesn't allow you to read street signs, addresses, or traffic signs and lights, then, even if you have passed the required vision test how ever many years ago, you should not drive. If you can't remember where you are or which pedal does what, then you shouldn't drive. I you hit people, buildings, and other stationary or large objects it is time to hand over the keys.
Now before you run off thinking what an inconsiderate, privilege revoking, unsympathetic person I am, hear me out. I know every driver, at some point or another, makes driving mistakes and breaks rules. I am talking about an overall slow reacting, loss of ability. I think that driving without the skills and ability to drive at an elderly age is akin to driving drunk at any age. I know that this general opinion of mine doesn't apply to ever single elderly person. There are exceptions to every rule. I do know that I was appalled to do some research and read the requirements for elderly people maintaining their driving privileges, and wow! I think public safety should come before political correctness. Come on here, this is just basic common sense. Lots of things change rapidly between the current time requirements set by our state goverment.
I have read all kinds of opinions from politicians , family members, police officers, and healthcare professionals. Many people agree that elderly people should not drive, but yet no one wants to go out on that proverbial limb and do anything to protect the elderly and the rest of us traveling America's roadways. I also know how difficult it is for family members to have to "talk" to their aging parents or relatives about giving up some of their freedoms. I cared for my 74 year old Granny during the last couple of years of her life, and no, they don't want people telling them what to do or how to live their lives. I know that taking away their driver's license takes away more that just driving, but we must do what is right. While I think the aged certainly have a say in what happens to them, not everyone wants to admit when they need help or if they can't do something they once did, for many years, competently and safely anymore.
So, at what age should the screening process tighten up for older drivers, 65, 70, 75? Should they take road tests, written tests, or just vision tests? What should the bench marks be, and how often should the tests be administered? What will the cost be? And finally, the part everyone seems to dread, when a person can no longer meet the requirements, who wants to be the big ol' meanie, and take away an old person's keys and license? What do yo think?