Towing of improperly parked vehicles
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
Any motor vehicle that is parked in violation of these regulations may be towed away or otherwise moved if a determination is made by a uniformed guard that it is a nuisance or hazard. A reasonable amount for the moving service and for the storage of the vehicle, if any, may be charged, and the vehicle is subject to a lien for that charge.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.