Which of the following vehicles is exempt from inspection?

A vehicle that is being towed is exempt from inspection because, at the moment of being towed, it is not being operated on the road. State inspection laws generally apply to vehicles that are actively in use, ensuring they meet safety and emissions standards while in motion. Since a towed vehicle is not being driven, it is not subject to the same inspection requirements as a vehicle that is operational.

In contrast, the other choices involve vehicles that, when used or operated, would typically need to comply with state inspection regulations. A privately owned motor home, for example, is still classified as a motor vehicle and must be inspected to ensure safety and compliance with emission standards. Similarly, a vehicle with expired registration is still considered a vehicle in operation until the registration is renewed, thus requiring it to meet inspection standards. A modified vehicle, depending on how it has been altered, could also still be in need of inspection to ensure it meets safety standards despite its modifications.