Yes, there are indeed many park benches specifically designed to discourage activities like sleeping or skateboarding. This practice is known as "hostile," "defensive," or "disciplinary" architecture. The goal is to subtly manipulate behavior in public spaces without the appearance of overt security measures.
To prevent sleeping, benches are often designed with individual armrests placed along the seating surface. These dividers make it impossible for a person to lie down. Other designs include slightly slanted seats, convex surfaces, or even segmented, small seats that are uncomfortable for prolonged sitting, let alone sleeping. Some benches incorporate metal bars or knobs at regular intervals.
To deter skateboarding, designers employ several tactics. Benches may have metal fins or studs installed along the ledges and edges that skateboarders would typically grind on. These are sometimes called "skatestoppers." Alternatively, the edges of the bench might be rounded or curved, eliminating the sharp angles necessary for skateboarding tricks. The materials can also be chosen to be less smooth, providing poor grinding surfaces.
While proponents argue these designs reduce vandalism and ensure benches are available for sitting, critics strongly condemn them. The primary criticism is that hostile architecture unfairly targets homeless populations, making their lives even more difficult by denying them a place to rest. It is seen as an inhumane way to sweep social problems out of sight rather than addressing their root causes. These benches ultimately make public spaces less comfortable and accessible for everyone, from an elderly person who might want to lie down to a teenager simply leaning on a ledge.