How does HOA keep owners from parking on cluttered streets?

I live in over 300 unit complex in Michigan that is over 20 yrs old. We have one car garage and some unit owners use their garage for storage or feel it's not the boards place to enforce the bylaws that garages and driveways need to be used first before parking on the street. We (the BOD) have been working to enforce the bylaw for parking to eliminate multiple cars on the road causing issue with traffic as well as residents walking around cars (we don't have common walkways) and putting themselves in traffic. We have a few residents that state the garage is not a common element and therefore cannot be forced to be told how and when to use their garage. Any clarification or prior experience with this?