This argument, and this article, completely miss the absolutely most significant engineering issue, as is typical when people start debating cages/ airbags/ harnesses in street vs race vehicles.
The biggest issue for people in a wreck is not whacking their head on the roll bar.
Race cars are, from an engineering perspective, a COMPLETE OPPOSITE approach than street cars and, in fact, compromise many safety concepts because they are designed for performance.
If you are in a wreck in a street car, the seat belt (or harness) won't save your life. The seat belt is designed to restrain you long enough to let the rest of the car save your life.
Your life will be spared because the energy will be absorbed in ways that are designed to direct those forces away from your mushy little body. Crumple zones, collapsible steering columns, drop away motor mounts designed to force the engine under the passenger compartment, stress points in chassis designed to absorb energy, side impact bars, fold under rear trunk areas and noses, impact absorbing bumpers, and a host of other generally passive engineering tricks all combine to absorb the energy otherwise destined to turn your brain into a bowl of Spaghetti-O's. The active restraints (seat belts, air bags, etc) are only supposed to keep you in place until the other parts of the car have done their job.
Street cars are designed to collapse, in a controlled manner.
Enter the racer. Let's face it, most of us are not engineers, and only know enough to get ourselves into trouble.
So, we figure out how to make a car go faster. But regardless of the type of racing you prefer, you will always come to the point where you realize making a car stiffer will generally make it faster.
So we build cages, but we include suspension pickups, effectively negating the crumple zones, both front and rear. Solid mounts will gain us a bit of torque to the wheels, but we will loose the drop away engine mounts. Harder suspension will corner tighter, but will have a more difficult time keeping the rubber on the pavement. Collapsible steering columns are heavy, side impact bars are unnecessary weight, air bags are ridiculous in a racer, impact absorbing bumpers are too heavy so we gut them, etc. etc. etc.
Everything those brilliant engineers put into the street cars to keep people safe, we undo, redo, disable, or work around.
Racing is compromising all the safety engineering that went into the car in the first place, and we then have to add after market racing safety gear to protect ourselves from ourselves, now that we've taken apart all the safety design in our cars.
For this reason, race cars aren't designed to collapse in a controlled manner like street cars. We generally lack the engineering capability in our backyards to accomplish this. They are designed to be rigid, and maintain a rigid compartment for the protection of the occupant, unless you've got several million to pay engineers of equal caliper to the OEM engineers to design new energy absorbing safety systems.
These are conflicting engineering principles. They are fundamentally incompatible.
So, rather than the absurdly simplistic question, "Will I whack my head on the rollbar?", we should be looking at the entire system, and asking, "Where will the energy be absorbed when this vehicle hits a concrete wall now that I have disabled all those nice safety devices the factory worked so hard to give me in the first place?"
Then we'll have a safe vehicle, on or off the street.
). That would certainly complicate the discussion, as it could potentially serve to stiffen the car in weird ways, yet fail to offer the protection it is supposed to.
