When I was a little bitty dude growing up in Ohio, I was very inquisitive. I asked lots of questions, and my mom answered most of them. One day while we were out driving somewhere, I saw a sign that said “No Outlet.”

“What does ‘No Outlet’ mean?” I asked.

“It means there’s no place to plug in your coffee pot,” she responded.

My mom and dad both laughed and then explained that it meant the same thing as “Dead End.” From then on whenever any of us saw a “No Outlet” sign, someone was sure to comment, “No place to plug in your coffee pot.” It became a standing joke.

That was more than 50 years ago.

I got to thinking that if “Dead End” and “No Outlet” were really interchangeable, then one would surely have supplanted the other over those 50 years. It stands to reason that if they mean the same thing, one must be newer or somehow more preferred than the other. It would slowly but inexorably overtake the older, less preferred sign. Personally, I favored “No Outlet” as the more preferred sign. It seemed newer and less likely to remind drivers of death.

After 50 years, however, I still see both signs. Sometimes there’s a “Dead End” sign, and sometimes there’s a “No Outlet” sign. This led me to reflect that the signs must differ in some way. Maybe the signs have different applications depending on the circumstances or environment.

In fact, a quick search turned up just such a difference encoded in the Manual on Uniform Traffic Control Devices, a publication used by street and road engineers to decide what kind of signs and traffic control devices to use for various situations. According to the Manual, the DEAD END sign may be used at the entrance of a single road or street that terminates in a dead end or cul-de-sac, while the NO OUTLET sign may be used at the entrance to a road or road network from which there is no other exit. So, technically, the “No Outlet” sign has wider applicability, since it could always replace a “Dead End” sign. But the “Dead End” sign could not always replace a “No Outlet” sign since it always applies to a single road.

Dead end implies the possibility of a living end, which also formed a phrase from my childhood. When Mom encountered some surprising innovation, she might say, “Well, ain’t that the living end.” It was on par with, “What will they think of next” or even just, “Wow!” I suppose most roads lead to a living end, but only a few lead to dead ends. That tends to give one a fairly positive outlook on the universe. Even if you make a wrong turn, you can turn back and get out the same way you got in. You can change direction and be fairly certain of reaching a living end instead of a dead end.