Since we entered New Mexico via I – 10 we found that EVERYTHING in southern and eastern New Mexico is FLAT, this extends into Texas as well. The only mountains or hills we have seen were the Guadalupe Mountains where Carlsbad Caverns is located. This area seems to rise out of nowhere and from the top all you can see is FLAT! Apparently due to the flatness of the area the wind blows all of the time; the only difference is how fast the wind is blowing. Is it 5 to 6 mph or is it 50 to 60 mph. As we are now moving westward there is always a head wind. Once we got to I – 40 the terrain changed from flat to non-stop rolling hills. You drive up one hill then go down the other side and then drive up the next hill. This apparently continues all the way across New Mexico! As you can imagine this non-stop head wind and rolling hills combination is HORRIBLE for the mileage. Our mileage from Clovis to Albuquerque was ONLY 7. 5 MPG. That is the worst mileage we have every gotten!