"Representational abstraction is a representation arrived at by removing unnecessary details."
Describe what this means in relation to a computer program which allows the user to enter a starting address $\mathbf{A}$ and a destination address $\mathbf{B}$ and returns a map of the route, the number of miles and the estimated journey time it will take to travel by car from $\mathbf{A}$ to $\mathbf{B}$.