John makes a number of good points here, the main one being that most safety improvements will significantly increase the cost of the car and running it and would likely result in the demise of the formula. It may sound crass and insensitive, but there's a great deal of truth in it.
Some ideas from me. Serious injury in Formula Ford usually occurs in one of three types of incident.
o Head on collision into a stationery object such as circuit banking.
o T-bone collision into the side of the car.
o Airborne rolling where the drivers head comes in contact with the scenery.
Without moving to a composite structure, you would need a more effective deformable front end on the car to handle high speed front end impact. This could improve the survival rate but obviously it doesn't eliminate it.
In terms of the side impact and airborne rotations, these could probably be handled by adopting bodywork along the lines of that used in karting [see the image below]. Of course it would need to be of a completely different structure and design, but what I'm getting at is how its enveloped so the wheels can't interlock and its crash tested. There is a downside to employing this however. It fosters more aggression in drivers because the hazzard of a crash is removed and results in more incidents.
In any event, I hope some of these thoughts help you.
