Great question — and the honest answer is that it really depends on where you are and who installed the bench. In a lot of modern cities, especially in parks, transit stops, and shopping districts, you're now more likely to sit on a bench made partly or entirely from recycled materials. Recycled plastic lumber is huge. It's often made from things like old milk jugs, detergent bottles, and plastic bags. The manufacturers shred, melt, and mold that waste into boards that look a bit like wood but don't rot, splinter, or need painting. Many of these benches still have metal frames, and that metal is frequently recycled steel or aluminum, though it's harder to tell just by looking.
That said, traditional materials haven't gone away. Plenty of urban benches are still made from new wood — pressure-treated pine, oak, teak, or tropical hardwoods — plus powder-coated steel or cast iron. You'll see these a lot in older parks, historic districts, or places where landscape architects want a classic look. The wood is usually sealed or painted, and over time it ages, cracks, or gets scratched. That's actually one of the ways to tell the difference.
If a bench looks like wood but has no grain variation, no knots, and the boards are perfectly uniform, there's a good chance it's recycled plastic or a wood-plastic composite. Give it a tap or press your thumbnail into an inconspicuous spot — recycled plastic feels denser and harder than most softwood, and it won't absorb water. You might also see a slight waxy sheen or tiny speckles of color in the material. On the ends of the boards, composite materials can look grainy or fibrous rather than like solid wood rings. Some benches even have a small stamped label or manufacturer name on the side; if you search it, you'll often find the exact recycled content percentage.
Metal parts are trickier. A bench frame made from recycled steel looks nearly identical to one made from new steel because both are usually powder-coated. Unless there's a sign or product listing saying the frame contains recycled content, you probably won't know for sure. In many eco-focused projects, the city or contractor will mention it on a plaque or in project documents.
So the short version is: modern urban benches are increasingly made from recycled materials, especially recycled plastic and composite lumber, but new wood and metal are still very common. If you're trying to judge a specific bench, look for too-perfect wood-like boards, check for labels, and think about the setting. If it's a new installation in a sustainability-minded area, recycled materials are likely. If it's an older bench with real wood grain and a bit of weathering, it's probably traditional timber and metal.