What is does this code do?? vector<..iterator>..

[mrbiggles]

I am going through someone's old code and trying to make sense of what's going on! I came across this snippet and can't quite fully understand what it's doing:

all_vehicles = vector<multiset<VehicleContainer>::iterator>(total_vehicles)

total_data is of type size_t but I've seen a similar call with int and VehicleContainer is just a generic class that contains a shared_ptr to a Vehicle and a few other member variables.

I'm guessing it's initializing a vector of pointers that will eventually point to each vehicle(?) Also, why can't I just use an int?