For broken bridge windows and doors, glass and aluminum are the two most commonly used materials. Glass is preferred for its transparency and ease of replacement, while aluminum offers durability and resistance to corrosion. According to a study by the American Iron and Steel Institute, aluminum doors have a lifespan of up to 30 years, making them a cost-effective long-term solution. Glass, on the other hand, is more susceptible to damage but can be quickly replaced. The choice between the two materials depends on the specific requirements of the bridge and the budget constraints.