I may be wrong but as I see you drawed this over a photo. It's not against the exact rules, but in this state this is very rough and ugly. Try to clear and streighten the line, because it wouldn't go through the queue. The frontal wheel doesn't have width, the frontal lines aren't parallel, the windshield's line isn't contigous... etc. You can see it and I'm sure that you can fix it. ;)
As a rule of thumb, don't outline black with gray.