Motorway problem

Imagine four towns in a square system with side length 1 mile.

You would like to connect all four towns by motorways, using the least amount of road (not necessarily the most efficient for any one particular town).

Here is one option – it would take 4 miles of road. Can you do better?

Once you have had plenty of time to think and try and find and evaluate the best route, watch this video for the solution.