45 mph in the hammer lane with his right turn signal on.
How fast did he drive on the mostly interstates he traveled on? Wind resistance drag is the square of the velocity. For example driving 50 mph verses 70 mph the wind drag is 98% greater. Some interstates will let us drive 80 mph. The wind drag is then 256% greater.
A real test is average driving conditions of stop and go and some interstate travel and country roads. On this test the Prius is far less but it is still outstanding in its gas mileage. It is a good car.
How many months did this jaunt take him?