They can also be relatively expensive. My second home of Brisbane has been building “active transport” bridges since the late 90s, and currently offers three ”green” crossings in the inner core, with four more in the works, along with three combined active-mass transit crossings (no road vehicles). One of active-only bridges, the Neville Bonner Bridge connecting the under-construction, $3.6B Queens Wharf development to the South Bank cultural complex, is expected to cost $100M.