Say you’re in the car with him — this is a hypothetical, of course — and he’s not really noticing the speed bumps. He blew through a stop sign. On one particular trip late last month he drove through a red light into a fender bender. No one was hurt. Maybe he was just tired, and this was a one-off? But he’s a little bruised up, and so is his ego, because afterward, the family had the Big Talk, to ask: Is it time to take the car keys away from Grandpa?

Some relatives think so. Others disagree. Grandpa has, historically, been a really good driver. He has been driving for, say, 54 years — big, cross-country trips, sometimes on challenging roads. He’s driven ancient Hondas and fancy Porsches. He insists he is still capable of driving. Just maybe not at night?

But so much is at stake: his safety, our peace of mind, the greater good. It’s a tough spot, for anyone. For everyone. Some families ignore their relative’s decline; some families obsess over it. How should we, as a countr — er, a family — have this conversation?

You have to “frame it from a loving perspective,” says Patrick Sullivan, 42, a Denver game designer who went through this phase recently with his family. “You’re talking about this enormously proud and successful person and saying: ‘This very basic activity you’ve been doing for 60 or 65 years — it’s no longer safe to do this, and you have to kind of come to grips with that reality, and what it implies about your future years.’”

It’s usually a fraught ping-pong between denial and overreaction, says Alexandra Crampton, an associate professor at Marquette University and expert in gerontology and conflict resolution.

“We tend to either say, ‘It’s not a big deal, this person’s basically the same as they’ve always been,’” says Crampton. “Or you jump to the other extreme, which is that this person can’t drive,” and therefore “needs to move into assisted living.”

“Being in the driver’s seat has different meanings for different people,” says an online video course for AARP called “We Need to Talk.” “For some, driving is a part of their identity.”

A man without his keys might feel like he’s going nowhere. A man without keys can’t pretend to outrun anything.

We don’t talk about aging enough, Crampton thinks, and that’s why we’re so ill-equipped to have this particular conversation with Grandpa. It’s also why many people who have something to say about his abilities are bringing their own anxieties about aging to the table.

“Oftentimes, you know, the difficult conversation isn’t this surface topic, like the driving itself,” she says. “It’s something underneath it. So, it could be the emotional conversation people aren’t having.” The child parenting the parent, for example. A sort of pre-grief.

Despite his resistance and bravado, Grandpa is probably afraid, too. After the fender bender, he knows his driving is under a magnifying glass, and his passengers are acting twitchy, and pressing down on a nonexistent brake pedal. Research has shown that older people who worry about being judged negatively according to a stereotype — say, that elderly people are bad drivers — may underperform the activity in question. For example, says Crampton, “if you’re worrying about remembering something, it can get a lot harder to remember it.”

We’ve been talking openly about how Grandpa is getting too old to drive ever since his last big road trip. (When was it, about four years ago?) Surely that makes him self-conscious. And so does the pressure. Some people have told Grandpa that he’s better than any other available driver. And other people have told him that he’s more likely to crash than anyone else.

Some of Grandpa’s colleagues have reluctantly given up driving. Some waited too long and got in accidents. One woman who worked with Grandpa kept driving well after people told her to give up the keys, and she died behind the wheel, and everyone’s been wringing their hands, in anger and regret, over the consequences.

“I don’t know that anyone has that self-awareness, when you get to that point where you have to say, ‘I’m not as fit as I used to be to do something,’” says Sara Spector, a Midland, Tex., attorney who has handled elder law issues, and who took the keys away from her father 15 years ago. “Usually somebody has to come to you and tell you that.”

But Grandpa doesn’t seem to be listening. Everyone’s hoping he’ll arrive at the same conclusion on his own. Or, as one of Grandpa’s friends might say: “He is beloved, he is respected, and people want him to make that decision, not me.” Preferably, soon.

Because, quite frankly, Grandpa’s been a bit erratic lately. We passengers are in the back seat completely freaking out, and a big crash is seeming more and more inevitable, as if we’re barreling in slow motion toward a semi in the oncoming lane unless someone reaches over and jerks the wheel …

A car. We’re definitely talking about a car, here.