Underinsured motor vehicle shall mean a motor vehicle with respect to the ownership, operation, maintenance, or use of which there is bodily injury liability insurance or a bond applicable at the time of the accident and the amount of the insurance or bond is less than or has been reduced by payments to persons, other than an insured, injured in the accident to less than the damages for bodily injury, sickness, disease, or death sustained by the insured. Underinsured motor vehicle shall not include an uninsured motor vehicle.