Remember when Musk claimed the roof of the Model S was so strong that it broke the testing machine, suggesting it's roof was unusually strong? Well, it turns out reality is a little different. The recent IIHS test of the Chevy Bolt shows that the Bolt's roof has a strength-to-weight ratio of 5.74 while the Model S in it's lightest S60 form has a ratio of only 4.33. The heavier S models score worse, with the 100D being rated only "acceptable". Even more interesting, the lighter Bolt can withstand a peak force of 20,042 pounds compared to 19,271 for the Model S. 2017 Chevrolet Bolt 2017 Tesla Model S The Bolt received the IIHS Top Safety Pick award, the first and only BEV on the list.