Yes, they do exist, but they are still a niche feature rather than the standard for public seating. When people say “built-in footrest” on a street bench, they usually mean a lower secondary rail, a rounded foot bar, or a slightly angled front platform set about 8 to 14 inches above the ground. It is not a padded lounger-style leg rest, but it gives your legs a different position and can make a real difference if you want to sit comfortably for longer.
You are most likely to find these benches along waterfront promenades, in parks designed for older adults, on university campuses, and in some transit waiting areas. Northern European and Japanese street furniture designers tend to include footrest bars more often because their public seating often focuses on ergonomics, posture support, and accessibility. If you search online, use terms like ergonomic public seating, outdoor bench with footrest bar, or public bench with secondary rail. Many manufacturers list the feature as a footrest rail or lower foot support in their specifications.
The reason these benches are not everywhere comes down to maintenance and safety. A lower rail can collect leaves, snow, or litter, and it can be a tripping hazard if it sticks out too far. Cities also need to keep clear paths for wheelchairs and strollers, so a built-in footrest on both sides can be a clearance problem on narrow sidewalks. Cost is another factor: a simple flat bench is cheaper to buy, install, and repair.
If your main goal is added comfort, it is worth searching specifically for a comfortable street bench with an integrated footrest or foot bar. Otherwise, you can get a similar effect by choosing a standard bench placed near a low step, planter edge, or raised curb. It is not a perfect substitute, but it helps more than you might expect.