My mistake. 30 degree incline, from my geometry days.
Same difference. A 30 degree incline is the same as a 30 degree grade or slope.
I'm assuming you mean 30% grade which is still extremely steep. Effectively what you saying is that your driveway, rises 60 ft. over a length of 200 ft. That would be difficult to even walk up.
To establish your grade, you need to know what the elevation difference is between your garage and the street. I.e , if your garage floor is 20 ft. higher than the street and your driveway is 200' long, that's a 10% grade.