Why are roll cages not allowed in domestic vehicles?

[LaEverett]

Domestic vehicles are not allowed to have roll cages for the following reasons: 1. Increased costs: Since roll cages are not made of ordinary steel but rather from cold-drawn seamless carbon steel pipes, installing them in household vehicles would significantly raise manufacturing costs. 2. Occupies space: Installing a roll cage in a household vehicle naturally reduces interior space considerably. To accommodate the roll cage, the rear seats would need to be removed. 3. Affects comfort: With a roll cage installed, many interior configurations would be removed, greatly diminishing the vehicle's comfort. 4. Illegal modifications: Ordinary vehicles are not permitted to undergo self-modifications, and installing a roll cage is considered illegal. Adding a roll cage inevitably involves altering the original vehicle structure, introducing more safety risks with unauthorized modifications.