Yes, it is absolutely possible to add a center armrest to a park bench—and in fact, this is a common strategy used by city planners, park managers, and even savvy homeowners to discourage people from stretching out across the entire seat. I have seen this implemented in urban parks, transit stops, and public plazas, and I can tell you it works quite effectively, though there are some important details to consider.
The short answer is: adding a center armrest divides the bench into two distinct spaces, making it physically uncomfortable to lie down horizontally. This is often called "hostile architecture" or "defensive design" by critics, but its primary goal is usually to maximize seating capacity and prevent one person from occupying an entire bench meant for multiple users.
From a practical DIY standpoint, if you want to retrofit an existing park bench, you will need to drill into the seat slats or frame and mount a durable, weather-resistant armrest. I would recommend using stainless steel or powder-coated metal brackets, paired with wood or recycled plastic for the armrest itself, to match the bench material. Make sure the armrest is at least 6 to 8 inches high, positioned roughly in the center of the bench length, and securely fastened with tamper-proof screws to discourage vandalism.
However, there is a trade-off. A center armrest can reduce the bench's functionality for other users—for example, parents trying to sit close to a small child, or couples wanting to sit side by side. It can also make cleaning the bench more difficult, as leaves and debris may get trapped around the base. Some cities have faced backlash for installing such features, as they are seen as unwelcoming to homeless individuals who may rely on public benches for rest.
If you are considering this modification, I would suggest first checking local regulations. Some public spaces have restrictions on altering furniture, and in certain areas, "anti-homeless" designs have been legally challenged. Alternatively, you might explore less aggressive solutions, such as installing armrests only on every other bench, or using curved bench designs that naturally discourage lying down without feeling punitive.
In summary: yes, you can add a center armrest to a park bench to keep people from lying down. It is a simple, cost-effective, and widely used method. Just be mindful of the community impact and try to balance public comfort with your original intent. A well-placed armrest can be a practical tool, not an unwelcoming barrier.