Regarding rollover protection, Toso said: "If you draw a line connecting the cockpit rim to the main roll hoop structure (above and behind the driver), the 2012 car provides more clearance to the driver’s helmet, 90mm versus 54mm on the 2011 chassis."
This clearance improvement came about from moving an even stronger roll hoop forward on the chassis. In addition, the U-shaped cockpit rim insert that protects the driver's head on the each side was made taller for more shielding. Toso said that structural improvements for this year also included added energy-absorbing structure behind (3-inch-thick) and below (1.25-inch-thick) the driver's seat, "which absorbs the hits in a rear impact and also the vertical load, if the car bottoms on the ground having already lost the four wheels."
As for the latter occurrence, Toso said that situation is covered by the Suspension and Wheel Energy Management System. "This consists of tethers that ensure that the suspension, wheels, and the wings do not fly off. And they are short enough to prevent these parts from impacting the driver seated in the cockpit."
With structural safety changes extensive for this racing season, next year the only structural differences in the offing for IndyCar involve having a variety of aero kits to tailor car performance to different team and track requirements.
Learn more about IndyCar at Littelfuse's Speed2Design site.