Thank you for the information and your question. The only law that may assist you in seeking the change in rules, or accommodation, that you are seeking is the Federal Fair Housing Act. The Act makes it unlawful for an HOA (or any other party that falls under the Act) "to refuse to make reasonable accommodations to rules, policies
, practices, or services when such accommodations may be necessary to afford persons with disabilities an equal opportunity to use and enjoy a dwelling."
So, as long as you have a doctor's note or statement that you cannot enter or exit your vehicle or house, from your garage, or wherever else you are allowed to park, because of a disability, then you should be accommodated. If you are not, then you can file a complaint with the U.S. Department of Justice
or the Colorado Attorney General
's Office, or you can file suit under the Act.
You can read more about the Act at: http://www.justice.gov/crt/about/hce/jointstatement_ra.php
Please let me know if you need any clarification. I would be glad to assist you further if I can.