58 Imperial does not have a neutral safety switch. What it has is a neutral starter switch. The neutral button is the starter button. The key does not activate the starter, it just opens the electrical circuit. I cannot say what is causing the problem's on this particular 58. There are a variety of answers, any one of which might be correct. When it happened to my 58, it was the coil, but it could just as easily be a bad connection or a starter motor problem. There is also a ballast resistor to be looked at as well. What the car needs is a mechanic to diagnose the problem. It will get worse and it won't always fail to start in a convenient place. Replacing the coil worked for me, but I chose to replace the ballast resistor and get the starter motor rebuilt not too very long after. I went from taking five attempts to getting the 58 going to it starting on the first try. Hugh