Drivers side window nets are mandatory here and to get something effective you have to buy race nets but I have found a alternative to them that give you the same effect . get two tie down straps from a hardware store the ones with the buckles that you can feed the strap back through and a dog clip we cut the buckles off with about 5 inches of strap on it and staple the strap down further on the strap so you can clip it around a center pillar keep the buckles spread apart and make a triangle the length of the door opening and fold it over the dog clip then staple it where it over laps, then cut some strips and staple them at approx 4 inch intervals and put a strip through the middle once this has been done you can the stitch it on a sewing machine with nylon like the one wrapped around the pillar in the photo this is very strong and will stop your head from coming out the door . they do say your head can stretch your neck up to 6 inches in a accident .