Personally, I've had my run ins with the HOA commandos. Not only will I not live in one, I won't live anywhere that's not at least partially zoned agricultural. With that said, you need to review the by-laws agreed to when you moved in. They can explain definitions related to the by-laws and many refer to commercial vehicles as described herein. In other words for the purpose of the by-laws, their definition is the binding one. Example, if you sign the by-law agreement and it stipulates that any 3 axle vehicle is an ice cream truck, you would be fighting with them about an ice cream truck, not a commercial vehicle. In summary if they have worded the by-laws correctly,, you may be swimming against a stiff current.