Start with the manufacturer's spec sheet, not just how the bench looks. A transit-stop bench should have a clear static load rating. In practical terms, I look for at least 500 to 750 pounds total distributed weight. That sounds high, but public seating takes abuse: three adults, heavy bags, someone standing on it, or a group of kids jumping. If the supplier can't tell you the tested load capacity, that's a red flag.
Next, look at the frame and slats. Steel frames with welded or through-bolted joints usually hold up better than thin punched metal or riveted assemblies. Check the gauge or wall thickness of the frame tubing. For steel, I prefer at least 11- to 14-gauge tube walls. For slats, solid wood, thick aluminum extrusions, or recycled plastic lumber are common. If slats flex when you push on them, they will sag fast.
Material matters. Powder-coated steel and cast iron are strong but need corrosion protection. Stainless steel hardware is a must near road salt or coastal air. Aluminum is lighter and corrosion-resistant, but it must be structurally reinforced; cheap thin aluminum benches can bend. Concrete and stone are extremely strong but are harder to move and can crack if poorly cast. Recycled plastic benches can be strong, but check the internal frame because some are all plastic and may creep under load in hot weather.
Mounting is often where benches fail. A bench can be strong on its own but become loose if it's only bolted through pavers or thin asphalt. At a transit stop, it should be anchored to a concrete pad or footing with tamper-resistant bolts. If it is surface-mounted, walk up and push it hard from the side. Any rocking or lifting means the anchors or base are not adequate. For in-ground mounts, look for cracked concrete around the legs.
Also check the underside. If you see rust, missing bolts, cracked welds, or bent frame members, do not trust it. Sit on the middle and on one end. Listen for creaks and feel for excessive bounce. A little flex is normal on long benches, but a sharp drop or visible bending is not.
Finally, if this is for a transit agency or city project, ask whether the bench meets the local transit authority's street furniture standards. Many agencies have approved models and minimum specifications. If you're just observing a bench already installed, report any wobble, exposed sharp edges, or broken slats to the agency that maintains the stop.