Google Street View
Location of Alien: Near Crystal Springs, Extra Terrestrial Highway (NV 375). The route has been officially named as "Extra Terrestrial Highway" due to many UFO sightings along this lonely stretch of road.
Google Street View - Unfortunately the Google Street View of the road sign shown above is very blurred, however it can be clearly seen in the Wikimedia Image;
Location of Road Sign: East of Rachael, Extra Terrestrial Highway (NV 375).
More info: Wikipedia and Nevada State Route 375