Since the early 70’s vehicle roofs have been required by the NHTSA to withstand a weight of 1.5 times the gross vehicle weight. It has been proposed by NHTSA that this standard be increased to withstand a force of 2.5 times the vehicle weight, a 66% increase in strength. In particular, this reinforcement would withstand additional stress on the driver’s side.
But in a foundational assessment, auto makers and safety specialists disagree on the fundamental reason for the danger associated with rollover accidents. Automakers argue that it is the rolling motion itself that causes most injury and which needs the most remediation, rather than the integrity of the roof panels. An institute spokesman stated that the actual injury mechanism caused by the roof crushing crashes is unclear, but that a clear correlation exists between safety and roof strength. Several safety groups, including Public Citizen, have argued for stronger roof standards.
Estimates also vary on what the additional reinforcement would cost auto makers but the figure cited by the NHTSA is approximately $100M, which the auto industry says is a significant underestimate. Similarly, the number of projected lives saved is in dispute. The NHTSA estimate is in the tens of lives per year, but IIHS says the figure is in the hundreds.