Flexible traffic bollards are upright posts designed to control or direct traffic. Unlike traditional, rigid bollards, flexible versions are constructed from materials that allow them to bend upon impact and return to their original position. This functionality is critical in high-traffic areas where accidental collisions with these posts can occur. Made from a variety of resilient materials, including rubber, plastic, or polyurethane, flexible bollards are engineered to withstand multiple impacts while maintaining their effectiveness.

Another important consideration is the environmental aspect. With increasing awareness of the need for sustainable urban planning, removable bollards can play a role in promoting eco-friendly initiatives. By controlling vehicle access, they can reduce congestion and pollution in heavily trafficked areas, thereby contributing to a cleaner environment. This aligns with Sydney's broader goals of promoting sustainable practices and improving air quality.

Manholes are usually round, primarily because roundness is the best shape to resist the compression of the earth; covers are round because they are easier to manufacture than square or rectangular shapes, they are easier to move by rolling, and they can't fall into the opening.^[5] But in the United Kingdom they are nearly always square, or rectangular, in shape, at least at street level. Manholes can also be found in a triangular shape (e.g. in Cambridge, and surrounding villages).^[6]