Extensible enum class

The following example demonstrates this: 

enum class Vehicle {
    CAR,
    BUS,
};

void drive(Vehicle vehicle);

enum class Transport : Vehicle {
    SHIP,
    PLANE,
};

void travel(Transport transport);
The enum Transport is then a strict superset. One can travel using any vehicle, but also by other means of transport, such as a ship or an airplane. Of course, this is not a valid C++ code. 
template <typename TDerived, typename TBase>
struct IsExtended {
    static constexpr bool value = false;
};