Exploring various portals into technology and mythology, science and fiction...
https://www.youtube.com/watch?v=OC5C9a2udjo
A bridge that started out as an undivided highway, eventually had a safety divider installed.
https://www.lindsay.com/usca/en/infrastructure/brands/road-zipper/case-studies/safer-golden-gate-bridge
https://en.wikipedia.org/wiki/Barrier_transfer_machine
https://therabbitportal.blogspot.com/search?q=bridges
https://therabbitportal.blogspot.com/search?q=highways