Dispute with our Homeowners' Association regarding parking our car on our driver way

It is going to be a matter of proving what is "impractical" and what everyone meant when they agreed to that term.  If there is room in the garage for two vehicles, but it is more convenient for you to park the second car somewhere else, it is going to be difficult for you to prove that it was impractical.  you did not provide any information as to why it is impractical - for example - do you have young children that need to be carried, is one driver disabled, does one driver go back and forth frequently - these are some examples of what will have to presented in order to prove that you complied with the terms of the agreement, and qualify for the exception that it was "impractical" to park in the garage.