Explicit template instantiation and combination explosion?

I am writing a policy pattern class, which looks like:

template<typename Worker, typename Location, typename Behavior>
class Driver {
public:

    Location location;
    Behavior behavior;

    Worker* worker;

    Driver();

    void start();

};

in the cpp file, I have this:

template <typename Worker, typename Exchange, typename Behavior>
Driver<Worker, Exchange, Behavior>::Driver(){
    worker = new Worker();
};



template <typename Worker, typename Location, typename Behavior>
void Driver<Worker, Location, Behavior>::start(){
    ;
};


template class Driver<WorkerStruct1, LocationStruct1, BehaviorStruct1>;

here is the problem, I have quite a few of WorkerStruct and LocationStruct and BehaviorStruct. The very reason that I use policy pattern is to avoid the 'combination explosion'.

however, if I have to instantiate all the templates, I will have a big pile of instantiation lines at the bottom of the cpp file. Say, I have 7 for each of these 3 components, then I have 7 * 7 * 7 = 343 lines.

Is this how policy pattern suppose to work?