Conn. Gen. Stat. § 52-183: Presumption of agency in motor vehicle operation.

In any civil action brought against the owner of a motor vehicle to recover damages for the negligent or reckless operation of the motor vehicle, the operator, if he is other than the owner of the motor vehicle, shall be presumed to be the agent and servant of the owner of the motor vehicle and operating it in the course of his employment. The defendant shall have the burden of rebutting the presumption.