It's not just about whether you can see there's an oncoming car. For example, if you can't read the road signs ahead until a few seconds later than someone with "normal" vision, your driving will be seriously affected due to lack of timely information, and the added mental burden of trying to compensate for this.
My contacts are -1.75 with -0.75x148 astigmatism and I can't make out peoples faces unless I'm practically standing next to them. Nevermind trying to read a menu board at a restaurant counter or trying to find my glasses if I misplace them. Driving would be totally out of the question for me.
I wear glasses with similar lens as yours. I only realized I had myopia after starting to go to university, and I only realized I had astigmatism around 2 years later. I guess the brain learns to correct the image, at the expense of some headache if you depend too much on it.
I'm struggling to think of a road sign that isn't either placed well in advance of when you need it, or something like a stop sign where blurriness doesn't matter.
Just street names, I guess? Those are a pain to navigate by anyway. You often already want to be in a lane by the time you can read the sign. The proper the way to relieve that mental burden is to have a navigator or GPS.
