New Mexico, you missed a spot!

The little snow storm that hit New Mexico and Texas delayed our travel plans to Midland by a couple days. Thanks to the awesome Greg Morgan, we knew New Mexico got a lot of snow. Well Texas did to, but since New Mexico is such a barren state to drive through with one hotel that is the one you have to worry about.
So on Sunday we decided it would be safe enough to travel, as they had reopened the road.
The roads were dry. Driving along I began to wonder why they had been closed the day before. The road in New Mexico dipped down into a small valley. In that valley was a stretch of maybe 50 feet with 12 inches of snow. One poor VW bus was laying on it's side having been I am sure one of the many victims of the snow patch.
So my question is why? Is it that the workers in New Mexico feel just for fun they will not plow one spot in the road? Or was it on a county line and they can't decided where the line is?