The symbol at the bottom of the “Evacuation Route” sign contains the letters CD, for Civil Defense.

I remember first noticing the CD logo during the annoying and disconcerting tests of the Emergency Broadcast System in the late 1970s – the ones that interrupted perfectly good reruns of “Johnny Sokko and his Flying Robot” and “Green Acres.”

I also recall seeing the symbol on signs like this one along highways when we went on family road trips.

There was a time I figured the signs would guide my family to some sort of fortified safety bunker in the event of a nuclear war. This was the kind of romantic scenario that went through a kid’s mind back in the 70s and 80s.

The naïve days of atomic bomb survival tactics like “duck and cover” were over. Few baby boomers wanted to talk with their kids about the real horror that awaited in the event Brezhnev got trigger happy.

My mom, on the other hand, was pretty nonchalant about responding to my questions the few times I asked her about the subject. When I was around 9 years old I asked her what it meant if the EBS tone wasn’t “only a test.”

“It means we probably don’t have long to live,” she told me.

One time she mentioned that we might try evacuating to someplace in Ohio if a nuclear war broke out (perhaps following a CD Evacuation Route sign). Then, she added, since Detroit was a major center of industry, it was likely we’d all be piles of ash before we got far. Even if we survived, she explained, we’d die a painful and horrible death in the radiation-strewn wreckage.

My mom, changed in ways I will never know by the death of my seven-year-old sister in 1980, was not one to mince words about these sorts of things.

So, the CD logo, like the faded “Fallout Shelter” signs that once adorned my elementary school, became a symbol of the end of the world – the source of a thousand bedtime prayers answered by nightmares.

When I saw this in the archives, it was as if a switch was flipped. My 10-year-old self, who played Missile Command at the arcade and watched “Wargames” on the big screen, was there in the archives storage room with me, relieved the sign had been relegated to a museum.

A moment later, I was alone again, a 39-year-old father of three, standing next to a dirty round piece of metal amid a million other artifacts. That’s when I realized that arrow pointing toward an evacuation route never really pointed the way ahead. It pointed up.