The Nebraska State Patrol or local law enforcement agency may grant a waiver of the standards in section 60-6,257 for reasons of safety or security or for medical reasons based on an affidavit signed by a licensed physician. Such waiver shall be in writing and shall include the date issued, the vehicle identification number, the registration number, or other description to clearly identify the motor vehicle to which the waiver applies, the name of the owner of the vehicle, the reason for granting the waiver, the dates the waiver will be effective, and the signature of the head of the law enforcement agency granting the waiver. Such agency shall keep a copy of the waiver until the waiver expires.