Let me warn you, i am no engineer, just a warehouse manager. I threw these together before I left today. It could be start.
Photo 1 shows a view of the catch fence from the top, looking straight down. Notice the main posts are set away from the wall, maybe 6 feet or so. Attached to the posts are 4-7 beams that are curved to reduce the angle of impact. They are attached to the main posts by an extremely powerful spring hinge type thing. On the end of the beams, we will call them absorption beams, is the steel netting, pretty much just like what we have now. Its not what does the damage.
Photo 2 shows the fence from the side. You can see how the absorption beams are spaced. This will allow them to "wrap" around the car that is penetrating the netting. The idea here is to have the absorption beams pushing the car away from the main posts and back on to the track.
Photo 3 shows another top view with the fence in action. We will look at Conway's accident at indy. He went airborne and directly hit a main post which ripped the car in half, and broke his back. With this new fence, he would first have made contact with the netting and as he continued
to penetrate the absorption beams would be "springing" and rotating against his car keeping it away from the main posts. The idea here is that he would just "slide" against the netting and return to the track with considerably less damage and certainly not an have an impact that would break his back.
Tracks could use the steel netting they already have and just move the fence posts back away from the wall a few feet. Most tracks have plenty of room between the wall the the grandstands, especially on the newer cookie cutter tracks.